HK1171506B - Blood glucose meter and blood glucose level measurement method - Google Patents

Abstract

Disclosed are a blood glucose meter and a blood glucose level measurement method which make it possible to measure blood glucose levels in an appropriate environment by reliably detecting changes in the ambient temperature of the blood glucose meter. An internal temperature thermistor for measuring the temperature inside the housing of the blood glucose meter is disposed inside the housing of the blood glucose meter, and an external air temperature thermistor for measuring external air temperature formed from a component having a low thermal capacity is disposed away from the center of the housing of the blood glucose meter. A blood glucose meter microcomputer evaluates whether or not temperature fluctuations are within the permissible range on the basis of the difference between the two temperatures. The blood glucose meter microcomputer temporarily halts glucose level measurement processing until the temperature fluctuations return to within the permissible range if the permissible range is exceeded immediately prior to blood glucose level measurement, and discontinues processing if the permissible range is exceeded during blood glucose level measurement.

Description

Blood glucose meter and method for measuring blood glucose level

Technical Field

The present invention relates to a preferable technique suitable for a blood glucose meter and a blood glucose level measurement method.

More specifically, the present invention relates to a blood glucose meter and a blood glucose level measuring method capable of quickly and reliably detecting a temperature fluctuation around the blood glucose meter and accurately measuring a blood glucose level in a state where the temperature fluctuation is stable.

Background

It is well known that diabetes is caused by abnormal insulin secretion from the pancreas or decreased sensitivity to insulin. In type 1 diabetes patients with complete cessation of insulin secretion, it is necessary to measure the blood glucose level before meals and administer insulin based on this value.

Conventionally, in order to measure a blood glucose level easily by a patient at home or by a family member, the applicant developed and manufactured a small-sized blood glucose level measuring device (hereinafter, referred to as "blood glucose meter") for the purpose of self-measurement. Further, the applicant is developing a blood glucose meter with various management functions for a ward and capable of handling a plurality of patients.

The blood glucose meter is a machine as follows: the blood glucose level is measured by a biochemical reaction caused by bringing blood into contact with a reagent, using the principle of converting a glucose level into a color concentration or an electric signal. Most of the reagents used in the blood glucose meters change their reaction rate with blood depending on the temperature around the time of measuring the blood glucose level. Therefore, the blood glucose meter incorporates a temperature sensor, and performs temperature correction calculation when converting the physical property value obtained at the time of measurement into a blood glucose level.

A prior art document considered to be relevant to the present invention is referred to as patent document 1.

Patent document 1: japanese patent laid-open publication No. 2007-10317

Disclosure of Invention

In particular, in a self-measurement blood glucose meter, the following situation often occurs: for example, a blood glucose meter is used in an environment where a rapid temperature change occurs, such as when the blood glucose meter is taken from a cold room into a warm room in winter. What happens when the blood glucose level measurement is performed under the above-described conditions will be described.

The blood glucose measuring chip itself impregnated with the reagent is mounted so as to be exposed to the outside of the blood glucose meter, and is a small article having a small heat capacity, and therefore, follows the ambient temperature relatively quickly. On the other hand, since the blood glucose meter itself is a machine having a corresponding volume, it has a high heat capacity. Since the temperature sensor is provided on the circuit board inside the blood glucose meter, it slowly follows changes in the ambient temperature. Namely, the following situation occurs: after the ambient temperature changes sharply, the temperature sensor cannot accurately measure the ambient temperature immediately. Therefore, the temperature correction does not function correctly, and as a result, the blood glucose meter measures an erroneous blood glucose level.

As described above, it is conceivable that temperature fluctuations that are not preferable for measuring the blood glucose level occur during use of the blood glucose meter.

Patent document 1 discloses a blood glucose level measuring instrument in which a temperature sensor incorporated in a housing is disposed close to an outer housing, thereby measuring the temperature of the outside air and correcting the temperature accurately.

However, since the heat remaining inside the housing of the blood glucose meter affects the measurement, the temperature correction may be incorrect only by measuring the temperature of the outer housing.

It is desirable that the housing of the glucose meter be compatible with, i.e., substantially equal to, the temperature of the ambient air.

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a new and useful blood glucose meter and blood glucose level measuring method capable of quickly detecting a temperature change in the surroundings and controlling a blood glucose level measuring operation based on the temperature change.

In order to solve the above problem, a blood glucose meter according to the present invention includes: a blood sugar level measuring part which drops blood on a measuring chip in a state that the measuring chip is mounted and outputs a signal corresponding to the amount of glucose in the blood; a chip mounting processing unit for confirming whether the measurement chip is mounted on the blood sugar measurement unit; a blood dripping standby processing part for confirming whether blood is dripped on the measuring chip; a measurement processing unit for obtaining a blood sugar level from the signal output from the blood sugar level measurement unit; a housing that houses a chip mounting processing section, a blood drop standby processing section, and a measurement processing section; an internal temperature sensor disposed inside the housing; an outside air temperature sensor provided at a peripheral portion of the housing apart from the inside temperature sensor; a temperature check processing unit that compares the temperature difference between the internal temperature sensor and the external air temperature sensor with a predetermined threshold value and determines whether or not the temperature change around the casing is suitable for measuring the blood glucose level; and a control unit that temporarily stops the processing in the chip mounting processing unit or the blood drop standby processing unit until the temperature test processing unit determines that the blood glucose level is suitable for measurement when the chip mounting processing unit or the blood drop standby processing unit is operated and the temperature test processing unit determines that the blood glucose level is not suitable for measurement.

That is, an internal temperature sensor for measuring the temperature inside the housing of the blood glucose meter is provided inside the housing of the blood glucose meter, and an outside air temperature sensor made of a member having a small heat capacity for measuring the outside air temperature is provided at a position away from the center of the housing of the blood glucose meter. The blood glucose meter is configured as follows: whether or not the temperature variation is within the allowable range is determined from each temperature difference, and if the temperature variation is outside the allowable range, the process is temporarily stopped until the temperature variation falls within the allowable range immediately before the blood glucose level is measured, and if the blood glucose level is being measured, the blood glucose level measurement process is interrupted.

By configuring the blood glucose meter as described above, it is possible to reliably detect temperature fluctuations around the blood glucose meter and perform blood glucose level measurement in an appropriate environment.

According to the present invention, it is possible to provide a new and useful blood glucose meter and blood glucose level measuring method capable of quickly detecting ambient temperature fluctuations and controlling blood glucose level measuring operation based on the temperature fluctuations.

Drawings

FIG. 1 is an external perspective view of a blood glucose meter according to an embodiment of the present invention.

FIG. 2 is a top view of a blood glucose meter, which is an example of an embodiment of the present invention.

FIG. 3 is a schematic view of an optical measurement unit.

FIG. 4 is an internal block diagram of a blood glucose meter.

FIG. 5 is a functional block diagram of a blood glucose meter.

FIG. 6 is a flowchart showing the overall process of the blood glucose meter.

FIG. 7 is a flowchart showing a chip mounting process.

FIG. 8 is a flowchart showing a blood dropping standby process.

FIG. 9 is a flowchart showing a measurement process.

FIG. 10 is a flowchart showing a temperature inspection process.

FIG. 11 is a diagram for explaining conditions of the temperature inspection process.

Fig. 12 is a flowchart showing an exception determination process.

FIG. 13 is a flowchart of a measurement process according to another embodiment.

Fig. 14 is a flowchart of an exception determination process according to another embodiment.

Detailed Description

Hereinafter, an embodiment of the present invention will be described with reference to fig. 1 to 14.

Fig. 1 is an external perspective view of a blood glucose meter according to an embodiment of the present invention.

Fig. 2 is a top view of a blood glucose meter, which is an example of an embodiment of the present invention.

The blood glucose meter 101 is a portable device such as a doctor, a nurse, or a patient who is held by hand like a mobile phone to measure a blood glucose level, and is formed in a shape and weight that can be easily held by one hand.

The blood glucose meter 101 can not only measure the blood glucose level but also check the name and ID of the patient as an additional function, store the measurement value data for each patient, and check the appropriate drug to be administered to each patient, if necessary.

The housing 102 of the blood glucose meter 101 is an elongated synthetic resin container. A cylindrical optical measurement unit 103 made of metal for measuring blood glucose level or the like is provided at the longitudinal end of the housing 102. An LED and a photodiode described below are incorporated in the optical measurement unit 103 which can also be referred to as a blood glucose level measurement unit.

The optical measurement unit 103 is formed in a shape in which a blood glucose measurement chip (hereinafter referred to as a "measurement chip") can be attached and detached. The used measurement chip can be detached from the optical measurement unit 103 by operating the eject lever 104 (reject lever).

A display panel 105 made of an LCD for displaying measurement results, confirmation items, and the like is provided on the front surface of the housing 102. An operation panel 106 having a plurality of buttons is provided beside the display panel 105.

The blood glucose meter 101 includes, in addition to the above components: a lithium ion battery, not shown, which is built in the housing 102, a barcode reader device, not shown, which reads a barcode, an IrDA interface, not shown, which transmits and receives patient data, measured blood glucose value data, and the like, but is not directly related to the present invention, and therefore, a detailed description thereof is omitted.

Although not directly visible from the external appearance of the blood glucose meter 101 in fig. 2, a circuit board 202 as a printed circuit board is built in the inside of the meter main body. A known microcomputer is mounted on the circuit board 202. The microcomputer operates by the power of the lithium ion battery, receives an operation command signal from the operation panel 106, drives the LED inside the optical measurement unit 103, measures a predetermined blood glucose level by the photodiode, and displays the measurement result and the like on the display panel 105.

The basic blood glucose measurement of the blood glucose meter 101 is structured as in the prior art. The outline will be briefly described below.

A measurement chip is attached to the optical measurement unit 103, and blood to be measured is aspirated by the measurement chip. The measurement chip contains a test paper 511 formed of a porous film such as polyethersulfone. When the blood aspirated by the measurement chip reaches the test paper 511, glucose in the blood reacts with a reagent contained in the test paper 511, and the reagent develops a color. The color reaction takes a time of several seconds to about ten seconds, but the reaction is affected by the ambient temperature.

Light emitted from an LED as a light emitting element is irradiated on a test sheet, and reflected light from the test sheet is received by a photodiode as a light receiving element. After a predetermined reaction time has elapsed, the analog light reception intensity signal obtained from the light receiving element is converted into a digital value, and the digital value is converted into a blood glucose level and displayed on the display panel 105.

The structure for measuring the blood glucose level is not limited to the optical measurement system using a color developing reagent, and may be a structure that can be used for blood glucose measurement in the related art, such as an electrochemical sensor system.

When the blood glucose level is measured as described above, the reaction time of the reagent contained in the test strip changes depending on the temperature. Therefore, the ROM, which is a component of the microcomputer in the blood glucose meter 101, stores a correction value of the reaction to the ambient temperature. The program of the microcomputer stored in the ROM is configured as follows: the temperature at the time of measuring the blood sugar level is detected, and an appropriate measurement value is calculated.

However, when the air temperature changes during the measurement, the correction value cannot be accurately derived. Therefore, the risk of deriving an erroneous blood glucose value is extremely high. That is, the temperature of the middle-warmer gas cannot be changed during measurement. Of course, even immediately before measurement, if the temperature changes, it is necessary to wait until the change is stable and then perform the blood glucose level measurement process.

In order to accurately detect that the temperature around the blood glucose meter 101 is stable, two temperature measuring elements are provided in the blood glucose meter 101.

One is an outside air temperature sensor which is provided at a position away from the center portion of the housing of the blood glucose meter 101 and thermally independent from the housing, and measures the temperature of outside air (hereinafter referred to as "outside air temperature").

The other is an internal temperature sensor, which is provided at the central portion of the housing of the blood glucose meter 101, and measures the temperature inside the housing (hereinafter referred to as "internal temperature").

The two temperature sensors do not change even after a certain period of time has elapsed, and when the difference in value between the temperature sensors is small, it can be determined that the entire housing of the blood glucose meter 101 "adapts" to the outside air temperature, that is, the temperature difference between the outside air temperature and the inside of the housing of the blood glucose meter 101 is small enough to measure the blood glucose level accurately.

An internal temperature thermistor 203 as an internal temperature sensor is mounted on the circuit board 202 in the same manner as other circuit components constituting a microcomputer or the like.

On the other hand, an outside air temperature thermistor 307 as an outside air temperature sensor is provided in the optical measurement unit 103.

Fig. 3 is a schematic diagram of the optical measurement unit 103.

The optical measurement unit 103 includes a tube 302, an LED303 housed in the tube 302, a photodiode 304, a base 305, and a glass window 306.

In a tube 302 made of metal such as stainless steel, an LED303 and a photodiode 304 are provided on a base 305. For dust protection, the base 305 is separated from the outside air by a glass window 306 made of a thin glass plate. A platinum wire is printed on the glass window 306, which constitutes an outside air temperature thermistor 307.

In order to measure the outside air temperature quickly and appropriately, the heat capacity of the outside air temperature thermistor 307 needs to be reduced. Therefore, the glass plate constituting the outside air temperature thermistor 307 is constituted by: 6mm in diameter and 0.5mm in thickness. The heat capacity of the glass plate is approximately 4 mJ/K.

A holding mechanism, not shown, for detachably mounting the measurement chip 308 is incorporated in the cartridge 302. When the measurement chip 308 is mounted, the test piece 511 is disposed to face the glass window 306.

[ hardware ]

Fig. 4 is an internal block diagram of the blood glucose meter 101.

The blood glucose meter 101 is a system constituted by a microcomputer, and is constituted by a CPU402, a ROM403, and a RAM404, and a bus 405 connecting these components. In addition to the above configuration, a portion mainly providing a data input function and a portion providing a data output function are connected to the bus 405.

The parts corresponding to the data input function of the blood glucose meter 101 include: an optical measurement unit 103 for obtaining blood glucose level measurement data important for the blood glucose meter 101, an internal temperature thermistor 203 and an external air temperature thermistor 307 for obtaining temperature data, a real-time clock 407, and a button operation unit 408 which is an operation panel 106.

An LED303 constituting the optical measurement unit 103 is connected to a driver 410 for driving the LED303 to emit light. The driver 410 performs drive control by the D/a converter 411.

The photodiode 304 constituting the optical measurement unit 103 is connected to an a/D converter 413 through an I/V converter 416.

The LED303 is required to irradiate the test paper 511 in the measurement chip 308 with light of an appropriate intensity, and is controlled to emit light based on emission intensity data stored in advance in the nonvolatile memory 414 described below. That is, the light emission intensity data is read from the nonvolatile memory 414, converted into an analog voltage signal by the D/a converter 411, and then power-amplified by the driver 410 to drive the LED303 to emit light.

The light emitted from the LED303 is irradiated onto the test piece 511 of the measurement chip 308, and the reflected light reflected by the test piece 511 is detected by the photodiode 304.

The signal current of the photodiode 304, which varies according to the intensity of light received by the photodiode 304, is converted into a signal voltage by the I/V converter 416, and further converted into numerical data by the a/D converter 413. Then, the converted numerical data is recorded in a predetermined area of the RAM404 and the nonvolatile memory 414.

The blood glucose meter 101 has an internal temperature thermistor 203 and an external air temperature thermistor 307, and the external air temperature of the environment in which the blood glucose meter 101 is located and the internal temperature of the blood glucose meter 101 itself can be measured from the resistance change of the thermistors. Similarly to the photodiode 304, the resistance value of the thermistor is converted into numerical values by the a/D converter 413, and the numerical data is recorded in a predetermined area of the RAM404 and the nonvolatile memory 414. Since it is not necessary to measure the light reception intensity and the air temperature at the same time, the photodiode 304 and the thermistor can share the a/D converter 413 in a time-sharing manner.

The real-time clock 407 is a known IC providing a date-time data output function, and is collectively mounted on a plurality of microcomputers, personal computers, and the like.

In the blood glucose meter 101 according to the embodiment of the present invention, the date and time information of the time when the blood glucose level is measured needs to be stored in the nonvolatile memory 414 in association with the patient data, and therefore the real-time clock 407 is provided.

The display panel 105, i.e., the LCD display section 415, is included as a part providing the data output function of the blood glucose meter 101.

Various screens are displayed on the LCD display section 415 by a program stored in the ROM403 and run by the CPU 402.

The elements constituting the microcomputer in the blood glucose meter 101 include a nonvolatile memory 414, in addition to elements providing data input/output functions, the nonvolatile memory 414 providing a data storage function and being formed of an EEPROM. The nonvolatile memory 414 stores information of the patient, setting data of the blood glucose meter 101, accuracy test data, and the like. The data stored in the nonvolatile memory 414 is exchanged with an external device via an infrared interface, a wireless interface, or the like, which is not shown in the figure.

[ software ]

Fig. 5 is a functional block diagram of the blood glucose meter 101. The diagram is directed to the functions provided by the microcomputer.

The internal temperature thermistor 203 and the external temperature thermistor 307 are supplied with power supply voltages through voltage dividing resistors R502 and R503, respectively. As is well known, since the resistance value of the thermistor changes according to the ambient temperature, the voltage between the terminals of the thermistor changes due to the change in the resistance value.

The a/D converter 413a converts the voltage between the terminals of the outside air temperature thermistor 307 and the inside temperature thermistor 203 into digital data.

The a/D converter 413a and the following a/D converter 413b are the same as the a/D converter 413 of fig. 4. The single a/D converter 413 is divided into a thermistor a/D converter 413a and a photodiode a/D converter 413b in a time-sharing and functional manner.

The temperature check processing unit 504 receives the interrupt clock output every 1 second from the interrupt clock generator 505, and performs temperature check processing based on the data of the outside air temperature thermistor 307 and the internal temperature thermistor 203. The result of the temperature check process is written in the first flag 506 and the second flag 507, which are flag variables provided in the RAM.

When the temperature check processing unit 504 determines that the air temperature required for measuring the blood glucose level is stable, the first flag 506 is set to logic "false" (the flag is lowered). Conversely, when the temperature check processing unit 504 determines that the variation in the air temperature exceeds the variation range necessary for measuring the blood glucose level, it is set to logic "true" (flag is raised).

The temperature check processing unit 504 determines that the air temperature fluctuates when the blood glucose level is being measured, and if the fluctuation exceeds the fluctuation range necessary for measuring the blood glucose level, the second flag 507 is set to logic "true". The other cases are set to logic "false".

The LED303 is applied with a power supply voltage via a voltage dividing resistor R508 and a driving transistor 509. A D/a converter 411 is connected to the base of the driving transistor 509, and the LED303 controls the presence or absence of light emission and brightness according to a change in the base current.

The photodiode 304 is applied with a power supply voltage through a voltage dividing resistor R510. The photodiode 304 generates a signal current when receiving the reflected light from the LED303 from the test paper 511 inside the measurement chip 308. The signal current is voltage-converted by the I/V converter 416, and further converted into digital data by the a/D converter 413 b.

The chip mounting processing section 512 checks whether or not the measurement chip 308 is mounted on the optical measurement section 103, and if it is already mounted, checks whether or not the chip 308 is normally mounted. Therefore, the D/a converter 411 drives and controls the LED303, and the a/D converter 413b obtains data of the amount of light reflected by the photodiode 304, thereby determining the mounting state of the measurement chip 308.

The blood drop waiting treatment section 513 verifies whether or not blood is dropped on the test paper 511 of the measurement chip 308. Therefore, the D/a converter 411 drives and controls the LED303, and the a/D converter 413b obtains data of the amount of light reflected by the photodiode 304, thereby determining the state of the test piece 511 in the measurement chip 308.

The measurement processing unit 514 performs measurement of the blood glucose level. Therefore, the D/a converter 411 drives and controls the LED303, and the data of the reflected light from the photodiode 304 is obtained from the a/D converter 413b, and the blood glucose level is calculated after a predetermined time has elapsed from the start of the measurement process. In addition, when the measurement process is normally completed, the measurement data is stored in the nonvolatile memory 414.

The controller 515 continues to monitor the states of the first flag 506 and the second flag 507, and controls the execution of the chip-mounting processor 512, the blood drop waiting processor 513, and the measurement processor 514.

The LCD display section 415 displays necessary characters, graphics, and the like, by the chip mounting processing section 512, the blood drop waiting processing section 513, the measurement processing section 514, and the control section 515.

The button operation unit 408 is an aggregate of button switches, and mainly the control unit 515 receives an operation input thereof and performs operation control. The button operation unit 408 is provided with a cursor button, an enter button, a function button, and a power button.

[ procedure of treatment ]

Hereinafter, the operation flow of the blood glucose meter 101 will be described with reference to fig. 6 to 9.

Fig. 6 is a flowchart showing the overall processing of the blood glucose meter 101.

When the process is started (S601), the blood glucose meter 101 executes a chip mounting process of confirming whether or not the measurement chip 308 is normally mounted (S602).

Upon completion of the chip mounting process, the blood glucose meter 101 executes a blood drop waiting process of confirming whether or not the blood of the patient has been dropped on the test paper 511 in the measurement chip 308 (S603).

When the blood drop waiting process is completed, the blood glucose meter 101 executes a measurement process for measuring the blood glucose level from the amount of reflected light at that time after a predetermined time has elapsed (S604), and the series of processes is terminated (S605).

After the process is completed (S605), when the next measurement is performed, the whole process is restarted (S601).

Fig. 7 is a flowchart showing the chip mounting process. Fig. 7 is a diagram showing the detailed processing contents of the chip mounting processing S602 in fig. 6, and is also a diagram showing the processing contents of the chip mounting processing unit 512 in fig. 5.

First, for convenience of explanation, the flow of the processing will be described with steps S709a, S709b, S709c, and S709d, which are exception determination processing described in fig. 7, being skipped.

When the process is started (S701), the chip mounting processing portion 512 confirms whether or not the measurement chip 308 is mounted on the optical measurement portion 103 (S702). Specifically, the chip mounting processing unit 512 outputs LED303 drive control data to the D/a converter 411, and intermittently controls the LED303 to emit light by the driver. Then, a voltage signal based on the reflected light obtained from the photodiode 304 is converted into data by the a/D converter 413 b. The chip mounting processing unit 512 compares the reflected light data with a predetermined threshold value, and determines whether or not the measurement chip 308 is mounted on the optical measurement unit 103.

In step S702, when the chip mounting processing unit 512 determines that the measurement chip 308 is mounted on the optical measurement unit 103 (yes in S702), the chip mounting processing unit 512 then confirms whether or not the measurement chip 308 is normally mounted on the optical measurement unit 103 (S703). When the measurement chip 308 is normally mounted on the optical measurement unit 103 (yes in S703), the chip mounting processing unit 512 displays an "OK" character string on the LCD display unit 415 (S704), and then ends a series of processing and returns to the entire processing (S705).

In step S702, if the chip mounting processing unit 512 determines that the measurement chip 308 is not mounted on the optical measurement unit 103 (no in S702), then the chip mounting processing unit 512 checks whether or not a character string of "chip error" is displayed on the LCD display unit 415 (S706). If the "chip error" character string is displayed on the LCD display section 415 (yes in S706), the chip mounting processing section 512 erases the "chip error" character string display displayed on the LCD display section 415 (S707), and then confirms chip mounting again (S702).

In step S703, if the chip mounting processing unit 512 determines that the measurement chip 308 is not normally mounted on the optical measurement unit 103 (no in S703), the chip mounting processing unit 512 displays a character string "chip error" on the LCD display unit 415 (S708), and then confirms the chip mounting again (S702).

The following three states exist in the mounting state of the measurement chip 308 on the optical measurement unit 103.

One is a state where the measurement chip 308 is not mounted on the optical measurement unit 103 (non-mounted state), and no in step S702.

The other is a state in which the measurement chip 308 is mounted on the optical measurement unit 103 but is not normally mounted (incomplete mounting state), yes in step S702, but no in step S703.

The other is a state in which the measurement chip 308 is mounted on the optical measurement unit 103 and is normally mounted (completely mounted state), and yes in step S702 and yes in step S703.

Since the measurement chip 308 is once removed and then the measurement chip 308 is tried to be mounted on the optical measurement unit 103 again in order to eliminate the chip error, if the "chip error" is displayed on the LCD display unit 415 at the time of the unmounted state, the display is erased at that time.

The above is a general processing flow of the chip mounting process. However, immediately before step S702, immediately before S703, and immediately before and after S704, there are exception determination processes S709a, S709b, S709c, and S709d, respectively. The exception determination processes S709a, S709b, S709c, and S709d are all subroutines having the same processing contents and are processing contents executed by the controller 515. The details of the exception determination processing will be described below with reference to fig. 12.

FIG. 8 is a flowchart showing a blood dropping standby process. Fig. 8 is a diagram showing the details of the blood drop waiting process S603 in fig. 6, and is also a diagram showing the details of the blood drop waiting process section 513 in fig. 5.

First, for convenience of explanation, step S804, which is an exception determination process shown in fig. 8, is skipped, and the flow of the process will be described.

When the process is started (S801), the blood drop waiting process section 513 checks whether or not blood is dropped on the test paper 511 in the measurement chip 308 (S802). Specifically, the blood drop waiting processing section 513 outputs the LED303 drive control data to the D/a converter 411, and controls the LED303 to emit light intermittently by the driver. Then, a voltage signal based on the reflected light obtained from the photodiode 304 is converted into data by the a/D converter 413 b. The blood drop waiting processing section 513 compares the reflected light data with a predetermined threshold value, and determines whether or not blood is dropped on the test paper 511.

In step S802, when the blood drop waiting processing section 513 determines that blood is dropped on the test paper 511 (yes in S802), the series of processing is terminated, and the process returns to the entire processing (S803).

In step S802, when the blood drop waiting processing section 513 determines that blood is not dropped on the test strip 511 (no in S802), it is confirmed again whether blood is dropped on the test strip 511 (S802). That is, circulation was performed until dropping of blood could be confirmed.

The above is a flow of a normal treatment in a blood drop standby treatment. However, step S804 immediately before step S802 is an exception determination process. The step S804 is a subroutine of processing contents similar to those of the exception determination processing of fig. 7, i.e., S709a, S709b, S709c and S709d, and the details thereof will be described below with reference to fig. 12.

Fig. 9 is a flowchart showing the measurement process. Fig. 9 is a diagram showing the detailed processing content of the measurement processing S604 in fig. 6, and is also a diagram showing the processing content of the measurement processing unit 514 in fig. 5.

When the process is started (S901), the measurement processing unit 514 starts a built-in timer (not shown) to measure the time required for the measurement (S902). Next, the measurement processing unit 514 checks the time indicated by the timer (measurement time) and checks whether or not the measurement is completed (S903).

If the measurement time reaches the end of measurement in step S903 (yes in S903), the measurement processing unit 514 advances the processing when the blood glucose level measurement processing is normally completed.

The measurement processing unit 514 reads digital data obtained by converting a voltage signal based on the reflected light obtained from the photodiode 304 by the a/D converter 413b, and performs predetermined arithmetic processing to obtain measurement data. The measurement processing unit 514 stores the measurement data in the nonvolatile memory 414 (S904).

Next, the measurement processing section 514 displays the measurement data on the LCD display section 415 as a blood glucose measurement value (S905). Then, the measurement processing unit 514 continues to check whether or not the used measurement chip 308 is separated from the optical measurement unit 103 (S906). Specifically, the measurement processing unit 514 outputs LED303 drive control data to the D/a converter 411, and the driver intermittently controls the LED303 to emit light. Then, a voltage signal based on the reflected light obtained from the photodiode 304 is converted into data by the a/D converter 413 b. The measurement processing unit 514 compares the reflected light data with a predetermined threshold value to determine whether or not the measurement chip 308 is out of the optical measurement unit 103.

If it is confirmed that the measurement chip 308 is detached (yes in S906), the series of processing ends, and the process returns to the entire processing (S907).

If the measurement time does not reach the end of measurement in step S903 (no in S903), the measurement processing unit 514 goes through an exception determination process (S908), checks whether or not the second flag 507 rises (no in S909), and then checks the measurement time again (S903).

The second flag 507 is a flag set by the temperature check processing unit 504 when the temperature variation exceeds the allowable range and the blood glucose level is measured in the exception determination processing in step S908. Therefore, if the temperature variation is within the allowable range, the measurement processing unit 514 passes through steps S908 and S909, and substantially executes the loop processing of step S903.

When it is confirmed in step S909 that the second flag 507 is set up (yes in S909), the measurement processing unit 514 advances the processing when the blood glucose level measurement processing has failed.

First, the measurement processing unit 514 interrupts the measurement operation (S910). Specifically, the timer started in step S902 is stopped, and the output of the LED303 drive control data to the D/a converter 411 is stopped. Further, the operation of the a/D converter 413b is also stopped, and the reading of data based on the output current of the photodiode 304 is interrupted. In addition, information indicating "measurement failure" is stored in the nonvolatile memory 414.

Next, the measurement processing unit 514 displays the character string "measurement has been interrupted" on the LCD display unit 415 (S911). Then, the measurement processing unit 514 continues to check whether or not the used measurement chip 308 is separated from the optical measurement unit 103 (S912). This process is the same as step S906, and thus detailed description is omitted.

If it is confirmed that the measurement chip 308 is detached (yes in S912), the measurement processing unit 514 erases the character string display of "measurement interrupted" displayed on the LCD display unit 415 (S913). Then, the measurement processing unit 514 lowers the second flag 507(S914), ends a series of processing, and returns to the overall processing (S907).

Fig. 10 is a flowchart showing the temperature check process. The temperature inspection process is a diagram showing the process contents of the temperature inspection processing unit 504 in fig. 5.

As illustrated in fig. 5, the temperature check processing unit 504 receives the interrupt clock output every 1 second from the interrupt clock generator 505 and performs processing. That is, the temperature check processing in fig. 10 is not related to the flow of the entire processing in fig. 6, and is an interrupt processing executed every second.

Upon receiving the interrupt clock start processing (S1001), the temperature check processing unit 504 measures the outside air temperature and the inside temperature (S1002). Specifically, the voltages of the outside air temperature thermistor 307 and the inside temperature thermistor 203 are converted into data by the a/D converter 413b, and the outside air temperature data and the inside temperature data are obtained based on the data.

Next, the outside air temperature data acquired by the temperature check processing unit 504 is stored in a memory (not shown) (S1003).

Next, the temperature check processing unit 504 subtracts the internal temperature data from the external temperature data to obtain the absolute value thereof, i.e., the temperature difference between the external temperature and the internal temperature. It is checked whether or not the temperature difference is equal to or higher than a threshold value of 1 deg.C (S1004).

If the temperature difference is not equal to or higher than the threshold value 1 ℃ in step S1004 (no in S1004), a value obtained by integrating the fluctuation of the outside air temperature acquired in the preceding 4 seconds is calculated, and it is checked whether or not the integrated value is equal to or higher than the threshold value 1 ℃ (S1005).

If either of the conditions in steps S1004 and S1005 is satisfied (yes in S1004 or yes in S1005), the temperature check processing unit 504 raises the first flag 506(S1006), and the series of processing ends (S1007).

The steps S1004 and S1005 are for verifying whether OR not the temperature variation exceeds the allowable range, and mean that the respective conditions are linked by an OR condition.

If the integrated value is not equal to or higher than the threshold value 1 ℃ in step S1005 (no in S1005), the temperature check processing unit 504 checks whether or not the temperature difference between the outside air temperature and the inside temperature calculated in step S1004 is equal to or lower than the threshold value 0.5 ℃ (S1008).

If the temperature difference is equal to or less than the threshold value of 0.5 ℃ in step S1008 (yes in S1008), a value obtained by integrating the fluctuation of the outside air temperature obtained in the previous 30 seconds is further calculated, and it is checked whether or not the integrated value is equal to or less than the threshold value of 0.5 ℃ (S1009).

When both the conditions of steps S1008 and S1009 are satisfied (yes at S1009), the temperature check processing unit 504 lowers the first flag 506(S1010), and ends the series of processing (S1007).

The above steps S1008 AND S1009 are steps of verifying whether or not the temperature variation falls within the allowable range, AND mean that the respective conditions are linked by AND conditions.

In either case of steps S1008 and S1009, if the condition is not met, the first flag 506 cannot be changed, and the series of processes ends (S1007).

Fig. 11 is a diagram for explaining conditions of the temperature check processing.

The horizontal axis of the graph is time and the vertical axis is temperature.

At this time, the outside air temperature changes abruptly from the temperature P1 to the temperature P2 at time t 1.

The outside air temperature sensor has a small heat capacity and is provided at a position thermally independent from the housing at the center of the housing of the blood glucose meter 101, and therefore, it is quickly approximated to the outside air temperature.

On the other hand, since the internal temperature sensor is provided on the circuit board 202 disposed in the center portion of the housing of the blood glucose meter 101, the center portion shows a slow temperature change due to a slow thermal response including the heat capacity of the air inside the housing of the blood glucose meter 101.

Therefore, it is found that the difference between the outside air temperature sensor and the inside temperature sensor becomes large in a short time when the temperature change occurs. This phenomenon is utilized as a condition for raising the first flag 506, that the temperature difference is 1 ℃ or more, or that the integral value of the fluctuation amount of the outside air temperature for 4 seconds is 1 ℃ or more.

After the temperature change occurs, and the first flag 506 rises at time t2, if the housing of the blood glucose meter 101 approximates the outside air temperature, the first flag 506 is lowered (time t 3). The threshold used in this determination is preferably smaller than the threshold when the first flag 506 is raised. This is because if the threshold is made completely the same, the conditions for raising and lowering the first flag 506 match, and there is a possibility that the vibration (the operation for raising and lowering the first flag 506 is repeated) will occur. Therefore, as a condition for lowering the first flag 506, the temperature difference is 0.5 ℃ or less, or the integral value of the fluctuation amount of the outside air temperature for 30 seconds is 0.5 ℃ or less.

Fig. 12 is a flowchart showing an exception determination process. The exception determination process is a diagram showing the processing contents of the control unit 515 in fig. 5.

As described in fig. 5, the controller 515 continues to monitor the states of the first flag 506 and the second flag 507, and controls the execution of the chip-mounting processor 512, the blood drop waiting processor 513, and the measurement processor 514. In this case, when a request for the exception determination process is received from the chip-mounting processing unit 512, the blood drop waiting processing unit 513, and the measurement processing unit 514, the exception determination process is executed, and based on the result, control is returned to the calling-out source or control is not returned until a predetermined condition is satisfied.

When the process is started (S1201), the control unit 515 checks whether or not the first flag 506 is raised (S1202).

If the first flag 506 rises (yes at S1202), the temperature check processing unit 504 can determine that the temperature variation exceeds the allowable range for measuring the blood glucose level. Therefore, the control section 515 next confirms whether or not the message for warning has been displayed on the LCD display section 415 (S1203). If not yet displayed (no at S1203), the control section 515 displays a message of a warning "please wait until the error disappears at a place where the temperature is stable" on the LCD display section 415 (S1204).

In step S1204, after displaying the warning message on the LCD display section 415, the control section 515 checks the state of the first flag 506 again (S1202). The temperature check processing unit 504 measures the outside air temperature and the inside temperature, and changes in the inside temperature are relatively moderate compared to the outside air temperature. Therefore, the temperature fluctuation determined by the temperature check processing unit 504 does not have a property of being immediately stable. As a result, the control unit 515 continues to loop through steps S1202 and S1203 until the internal temperature approaches the outside air temperature.

When the internal temperature is close to the outside air temperature, the temperature fluctuation is within the allowable range. Then, the temperature check processing section 504 executed every second lowers the first flag 506.

In step S1202, if the first flag 506 is not raised (no in S1202), the temperature check processing unit 504 recognizes that the temperature fluctuation is within the allowable range for measuring the blood glucose level. That is, here, the loop of steps S1202 and S1203 can be finally disengaged. Therefore, the control section 515 next confirms whether or not a message of warning has been displayed on the LCD display section 415 (S1205). If it has already been displayed (yes at S1205), the display of the message displayed on the LCD display section 415 is canceled (S1206).

Next, the control unit 515 checks whether or not the measurement process is currently performed (S1207). If the measurement process is being performed (yes in S1207), the control unit 515 raises the second flag 507(S1208), and returns the process to the call-out source (S1209).

If no warning message is displayed in step S1205 (no in S1205) or if no measurement is being performed in step S1207 (no in S1207), the process returns to the source of call-out without any processing (S1209).

As described with reference to fig. 7, 8, and 9, the exception determination process is executed intermittently among the processes constituting the overall process. When the temperature variation is within the allowable range, nothing is moved to the next process. However, if the temperature variation exceeds the allowable range, the steps S1202 and S1203 of the exception determination process are repeated until the temperature variation falls within the allowable range, and if not, the loop cannot be separated from the loop and the process cannot be shifted to the next process.

Further, the exception determination processing called out in the measurement processing shown in fig. 9 is in the measurement processing. When temperature fluctuation occurs during measurement processing, the blood glucose measurement value at that time is highly likely to include a large error, and therefore cannot be used as an accurate measurement value. Therefore, the blood glucose level measurement process needs to be interrupted.

Therefore, the exception determination process includes a process of raising the second flag 507 indicating that the temperature variation occurs during the measurement process.

If a temperature variation occurs in the measurement process, a warning message is displayed in step S1204. When the temperature fluctuation is stable, the warning message is canceled in step S1206, but the process of "canceling the warning message" makes it clear that the temperature fluctuation has occurred immediately before that time. Therefore, immediately after step S1206, it is confirmed whether or not the measurement is in progress (S1207), and if so, the second flag 507 is raised (S1208).

In the present embodiment, the following application examples can be considered.

(1) The exception judgment processing is called only from the chip mounting processing and the blood drop waiting processing, and if the measurement interruption processing different from the exception judgment processing is performed in the measurement processing, the second flag 507 is not necessary.

Fig. 13 is a flowchart of a measurement process according to another embodiment, and fig. 14 is a flowchart of an exception determination process according to another embodiment. The above-described processing can be replaced with the measurement processing of fig. 9 and the exception determination processing of fig. 12, respectively.

Hereinafter, only the differences between fig. 13 and fig. 9 will be described.

If the measurement time does not reach the end of measurement in step S1303 (no in S1303), the measurement processing unit 514 checks whether the first flag 506 rises (S1308). If the first flag 506 does not stand (no in S1308), the temperature variation is within the allowable range, and therefore the measurement processing unit 514 passes through step S1308 and substantially executes the loop processing in step S1303.

When it is confirmed in step S1308 that the first flag 506 is raised (yes in S1308), the measurement processing unit 514 advances the processing when the blood glucose level measurement processing has failed.

First, the measurement processing unit 514 interrupts the measurement operation (S1309). Specifically, the timer started in step S1302 is stopped, and the output of the LED303 drive control data to the D/a converter 411 is stopped. Then, the operation of the a/D converter 413b is also stopped, and the reading of data based on the output current of the photodiode 304 is interrupted. In addition, information indicating "measurement failure" is stored in the nonvolatile memory 414.

Next, the measurement processing unit 514 displays a character string of "measurement interrupted" on the LCD display unit 415 (S1310). Then, the measurement processing unit 514 continues to check whether or not the used measurement chip 308 is separated from the optical measurement unit 103 (S1311).

If it is confirmed that the measurement chip 308 is detached (yes in S1311), the measurement processing unit 514 erases the character string display of "measurement interrupted" displayed on the LCD display unit 415 (S1312). Then, the measurement processing unit 514 ends the series of processing and returns to the overall processing (S1307).

In fig. 13, unlike fig. 9, the exception determination processing is not called, and the measurement processing unit 514 confirms the first flag 506 as it is, and immediately interrupts the measurement operation if the first flag 506 rises. Therefore, in the measurement processing of fig. 13, the message of the warning "please find that the waiting temperature is erroneously lost in a stable place" displayed in the exception determination processing is not displayed on the LCD display portion 415.

Hereinafter, only the differences between fig. 14 and fig. 12 will be described.

In step S1402, if the first flag 506 is not raised (no in S1402), the temperature check processing unit 504 determines that the temperature variation is within the allowable range for measuring the blood glucose level. Therefore, the control section 515 next confirms whether or not a message of warning has been displayed on the LCD display section 415 (S1405). If the message is displayed (yes in S1405), the display of the message displayed on the LCD display section 415 is canceled (S1406). Then, the series of processes ends (S1407).

If the warning message is not displayed in step S1405 (no in S1405), nothing is done to return the process to the call-out source (S1407).

The flowchart of fig. 14 differs from fig. 12 in that there is no step of confirming whether or not the second flag 507 is operated during measurement.

The operation of the blood glucose meter 101 when the processing procedure is replaced will be described with reference to the flowcharts of fig. 13 and 14.

When the temperature variation exceeds the allowable range in the measurement process, it is confirmed that the first flag 506 rises in step S1308 of fig. 13, and the measurement is interrupted in step S1309. When the measurement chip 308 is detached in step S1311, the process returns to the entire process in step S1307. However, the flow of processing from step S1308 to step S1307 after passing through step S1312 does not include processing in which a message indicating "please wait for the warning of disappearance of errors in a place where the temperature is stable" in the exception determination processing is displayed on the LCD display unit 415, and processing in which the process continues to wait until the first flag 506 falls in a loop. That is, when the measurement fails and the measurement chip is removed from the optical measurement unit 103, the temperature variation is highly likely not to fall within the allowable range.

The above-described processing is executed in the exception determination processing (step S709a in fig. 7) executed in the initial stage of the chip mounting processing executed next to the measurement processing.

As is clear from the above description, even if the processing in fig. 9 and 12 is replaced with the content of the flowcharts in fig. 13 and 14, substantially the same operational effects are obtained.

(2) The above embodiment has been described for a blood glucose meter for a ward, but the same embodiment can be applied to a simple self-measurement blood glucose meter.

In the present embodiment, a blood glucose meter is disclosed.

An internal temperature thermistor for measuring the temperature inside the housing of the blood glucose meter is provided inside the housing of the blood glucose meter, and an external air temperature thermistor for measuring the external air temperature, which is composed of a member having a small heat capacity, is provided at a position thermally independent from the housing at the center of the housing of the blood glucose meter. Further, the microcomputer of the blood glucose meter includes the following processes: whether or not the temperature variation is within the allowable range is determined from each temperature difference, and if the temperature variation is outside the allowable range, the process is temporarily stopped until the temperature variation falls within the allowable range immediately before the measurement of the blood glucose level, and if the blood glucose level is being measured, the blood glucose level measurement process is interrupted.

By configuring the blood glucose meter as described above, it is possible to reliably detect temperature fluctuations around the blood glucose meter and perform blood glucose level measurement in an appropriate environment.

The present invention has been described above with reference to the embodiments of the present invention, but the present invention is not limited to the embodiments described above, and other modifications and application examples are also included without departing from the spirit of the present invention described in the claims.

Description of the symbols

101.. glucometer, 102.. casing, 103.. optical measurement portion, 104.. trip rod, 105.. display panel, 106.. operation panel, 202.. circuit substrate, 203.. internal temperature thermistor, 302.. barrel, 303.. LED, 304.. photodiode, 305.. base, 306.. glass window, 307.. external temperature thermistor, 308.. measurement chip, 402.. CPU, 304.. ROM, 404.. RAM, 405.. bus, 407.. real-time clock, 408.. button operation portion, 410.. driver, 411.. D/a converter, 413.. a/D converter, 414.. nonvolatile memory, LCD, 415.. display portion, R502, R503, r.508.. temperature processing portion, 510.. temperature thermistor, 302.. barrel, 303.. LED, 304.. photodiode, 305.. base, 306.. glass window, 307.. external temperature thermistor, 308.. measurement chip, 402.. CPU, 402.. once 505.. an interrupt clock generator, 506.. a first flag, 507.. a second flag, 509.. a driving transistor, 511.. a test paper, 512.. a chip mounting processing portion, 513.. a blood dropping standby processing portion, 514.. a measurement processing portion, 515.. a control portion

Claims (6)

1. A blood glucose meter having:

a blood sugar level measuring section for dropping blood on a measurement chip in a state where the measurement chip is mounted, and outputting a signal corresponding to the amount of glucose in the blood;

a chip mounting processing unit that checks whether or not the measurement chip is mounted in the blood glucose level measurement unit;

a blood drop standby processing unit for confirming whether blood has been dropped onto the measurement chip;

a measurement processing unit that obtains a blood glucose level from the signal output from the blood glucose level measurement unit;

a case that houses the chip mounting processing section, the blood drop waiting processing section, and the measurement processing section;

an internal temperature sensor disposed inside the housing;

an outside air temperature sensor provided at a peripheral portion of the housing apart from the inside temperature sensor;

a temperature check processing unit that compares a temperature difference between the internal temperature sensor and the external air temperature sensor with a predetermined threshold value, and determines whether or not a temperature change around the casing is suitable for measuring a blood glucose level; and

and a control unit that temporarily stops the processing in the chip mounting processing unit or the blood drop waiting processing unit until the temperature inspection processing unit determines that the measurement of the blood glucose level is appropriate, when the temperature inspection processing unit determines that the measurement of the blood glucose level is not appropriate while the chip mounting processing unit or the blood drop waiting processing unit is operating.

2. The blood glucose meter according to claim 1, wherein the blood glucose level measuring portion is provided at a peripheral edge of the housing,

the outside air temperature sensor is provided in the blood sugar level measurement unit.

3. The blood glucose meter according to claim 1 or 2, wherein the temperature check processing unit determines that the change in temperature around the housing is not suitable for measuring the blood glucose level when the temperature difference is equal to or greater than a first threshold value, and determines that the change in temperature around the housing is suitable for measuring the blood glucose level when the temperature difference is equal to or less than a second threshold value that is smaller than the first threshold value.

4. The blood glucose meter according to claim 1 or 2, wherein the temperature check processing unit determines that the temperature change around the housing is not suitable for measuring the blood glucose level when the integrated value of the temperature change in the first latest time is equal to or greater than a third threshold value, and determines that the temperature change around the housing is suitable for measuring the blood glucose level when the integrated value of the temperature change in a second latest time, which is longer than the first latest time from the current time, is equal to or less than a fourth threshold value, which is smaller than the third threshold value.

5. The blood glucose meter according to claim 1 or 2, wherein the control unit interrupts the measurement processing unit when the temperature check processing unit determines that the measurement of the blood glucose level is not appropriate while the measurement processing unit is operating.

6. A method for measuring a blood glucose level, comprising:

a chip mounting process of confirming whether or not a measurement chip is mounted on a blood sugar level measurement section which drops blood on the measurement chip in a state where the measurement chip is mounted and outputs a signal corresponding to the amount of glucose in the blood;

blood dripping standby treatment, namely confirming whether blood is dripped on the measuring chip or not after the chip mounting treatment;

a measurement process of obtaining a blood glucose level from the signal output from the blood glucose level measurement unit after the blood drop waiting process;

a temperature check process of comparing, at predetermined time intervals independently of the chip mounting process, the blood drop waiting process, and the measurement process, a temperature difference between an internal temperature sensor provided inside a case of the blood glucose meter and an external air temperature sensor provided at a peripheral portion of the case apart from the internal temperature sensor with a predetermined threshold value, determining whether or not a temperature change around the case is suitable for measuring a blood glucose level, and setting a determination result as a flag; and

and a control process which is called from the chip mounting process and the blood dripping standby process, and temporarily stops the processes of the chip mounting process and the blood dripping standby process until the flag changes to a state indicating that the blood glucose level is suitable for measurement when the flag indicates that the blood glucose level is not suitable for measurement.