HK1159241B - Hand-held device for measuring an analyte concentration in a sample of a body liquid - Google Patents

Description

Hand-held device for measuring the concentration of an analyte in a sample of a body fluid

Technical Field

The present invention relates to a hand-held device for measuring the concentration of an analyte in a sample of a body fluid, having the features as defined in the preamble of claim 1. Such hand-held devices are known from the WO 2007/030457 a1 patent application and are used for quantitative analysis of body fluids (e.g. urine, blood and interstitial fluid), i.e. for measuring the concentration of medically important analytes (e.g. lactate, cholesterol and in particular glucose).

Background

Such handheld devices may be carried around by a user and are required, for example, by diabetics who must measure their glucose concentration from their blood samples and/or interstitial fluid several times during the day.

The values measured in this way can be stored in a memory of the measured values of the hand-held device for later transmission to an external evaluation unit, for example, a Personal Computer (PC) of a doctor. By evaluating the measured values obtained over a period of time, it is possible to optimize the medication of chronic diseases, such as diabetes. Modern handheld devices thus contain a clock so that when the measurement results are later evaluated, the developed analyte concentration over time can be verified together with the stored time information.

The time-dependent relationship between the different measured values may be distorted when the setting of the clock is changed. This can be avoided by providing the hand-held device with an internal clock whose settings cannot be changed by the user, such a system being known from DE 19733445a 1. The concentration of medically relevant analytes will typically vary with the cadence of the day, however, it is desirable to provide a hand-held device with a clock with a setting function to allow the time of day to be adjusted between summer and winter time or between different time zones. In order to ensure that the evaluation of the measured values obtained over a period of time is not distorted, such time adjustments need to be recorded.

Patent application WO 2007/030467 discloses a hand-held device in which the measured values and the date and time of the measurement at which each value was obtained are combined to form a measured value data set which is continuously stored in a memory of measured values. When the clock is set, both the magnitude and direction of the change are stored for this purpose in the memory (buffer log), so that individual information can be taken into account later on in evaluating the measured values.

Disclosure of Invention

It is an object of the present invention to provide a method of evaluating a sequence of measured values of a hand-held device with few inputs and without being falsified by changes in the time settings that have been implemented.

This object is achieved by a hand-held device having the features as defined in claim 1 of the present application. Further advantages and developments form the subject of the dependent claims.

Each time the clock is set, the hand-held device according to the present invention generates a time correction data set showing the set magnitude and direction and stored in the memory of the measured values of the hand-held device together with the measured value data set including information on each measured value and the date and time at which the data set was generated. Thus, a chronological sequence of the time-corrected data set and the measured value data set is generated in the measured value memory of the hand-held device according to the invention. The time correction data sets and the measured value data sets are thus stored in the measured value memory in accordance with the times at which the respective data sets were generated. This provides the following advantages:

a single reservoir may be sufficient for a hand-held device according to the invention. Thus saving components and associated manufacturing costs.

The clock of the hand-held device according to the invention can be set as often as desired, the number of time correction data sets that can be stored between measured value data sets of a succession of measured values being limited only by the size of the memory of the measured values.

The position of a time correction data set in a series of measured value data sets of measured values unambiguously defines the measured value data set associated with the respective time correction data set. A certain time of the setting (i.e., date and time) that is implemented will not be needed for later evaluation, and therefore, need not be recorded or stored, so that the time correction data set of the hand-held device according to the present invention can be given a very simple structure. The storage location of the time correction data set in the memory of the measured values and the magnitude and direction of the clock adjustment are sufficient to perform a series of correction evaluations of the measured value data set.

The handheld device according to the invention can be equipped with an extremely simple and cost-effective control unit, taking into account that time and time correction information do not have to be evaluated in the handheld device. The external device can retrieve a chronological sequence of data sets from the memory of the measured values of the hand-held device without difficulty via a hardware interface and the data sets can be evaluated at any time, all relevant information being contained in the chronological sequence of data sets.

The evaluation can be limited to any desired part of the chronologically ordered sequence of the measured value data set and the time correction data set. For example, the time-dependent relationship between successive measured value data sets of a desired number of times is clearly recorded in the time correction data sets between these measured value data sets, so that any desired data set portion can be correctly evaluated without any additional information. This facilitates the later use of the data obtained with the handheld device according to the invention by an external device, such as a doctor's PC, and the repeated evaluation of the data.

In the case of partial loss of data, the residual portion of the data does not become useless, since the evaluation can be limited to any desired number of consecutive data sets.

An advantageous further development of the invention provides that the measured value data sets and the time correction data sets have the same length. This helps to simplify the storage and management of the measured values and the serial (string) to be stored, since the data sets in the measured values storage have the same length.

The measured value data set and the time correction data set may be distinguished by a special data field or flag. Preferably, however, the time-corrected data set is identified by a symbol which begins at the same position relative to the beginning of the data set as the beginning of the field containing the measured value in a measured value data set. In this way, the data set can be given an advantageously short length, since no additional fields are required for differentiation. This is because the token proposed by the present invention may comprise a string of characters or bits that represent a physiologically possible value in a measured value field of a measured value data set. According to a particularly advantageous solution, the marking may comprise a string of characters starting with the number 9, in particular 99.

Having the token start with a serial number representing the number 9 makes it possible to use the bit string 99 or 999 as a token for a time-corrected data set in a data field containing measured values corresponding to density values that are never encountered in practice in measured value data sets.

It is preferable that the marks of the time correction data sets have the same length, because the field of the measured value data set contains the measured value. Even though two digits 9 followed by any third digit is sufficient as a sign for a time-corrected data set, a greater number of characters or digits may provide better security against writing or reading errors.

Preferably, the marker for identifying the time correction data set is arranged at the beginning of the time correction data set. This allows the time correction data set to be recognized.

Drawings

Further details and advantages of the invention are described below with reference to the embodiments and the drawings. In the drawings:

FIG. 1 shows one embodiment of a handheld device in accordance with the present invention; and

FIG. 2 shows a data structure of a data set generated by the handheld device.

Detailed Description

Fig. 1 shows an exemplary embodiment of a handheld device 1 for medical use for determining the concentration of an analyte in a sample of a body fluid of a human or animal. In the embodiment shown, the handheld device 1 is a blood glucose meter designed for use by diabetics to determine the glucose concentration in samples of blood or interstitial fluid.

For the measurement, a body fluid sample is applied to the test section of the carrier tape 2 and, after a transport step of a carrier tape of suitable length, the concentration of the analyte in the sample can be measured photometrically or electrochemically by a measuring unit in the device 1. It is possible to construct the hand-held device 1 in a manner that facilitates the determination of concentration in the form of a test strip of consumable material. The test element may be stored in a cartridge of the device or may be introduced with the sample provided through an opening in the housing. The housing part 6 is made separable in order to load fresh consumable material, a cassette accommodating the carrier tape 2, or in order to replace the battery in the battery compartment.

The measurement of the analyte concentration is displayed by a display means 3, preferably a liquid crystal display, such as a segment display. The measured values may be displayed together with a representation of the date and time provided by a clock built into the hand-held device 1. The control unit of the hand-held device 1, such as a microprocessor, generates a measured value data set from each measured value and from the date and time and writes the data set into a memory of the measured values, which data set can be read by an external device via the hardware interface 5.

In the embodiment shown, the hardware interface is designed for a plug-in connection. However, it is also possible to design the hardware interface as a wireless data transmission.

An operating element 4 which can be actuated by a user is provided for operating the device 1, in particular for setting a clock. When the built-in clock is set, the control unit of the device 1 generates a time correction data set defining the set magnitude and direction and writes the data set into the memory of the measured values, so that a time-ordered sequence of time correction data sets and measured value data sets is generated in the memory of the measured values. The chronological order is dependent on the point in time at which the data records were generated and is derived automatically on the fact that the data records are inserted in the memory of the measured values in such a way that one data record follows another.

FIG. 2 shows the structure of the data set stored in the memory of the measured values. There is shown a schematic representation of four consecutive data sets M1, T, M2, M3, which represent a fragment of the sequence stored in the memory of the measured values. The data sets M1, M2 and M3 are measured data sets, and T is a time correction data set. The data sets M1, M2, M3, and T all have the same length and include four data fields A, B, C, D.

The first data field A has a length of four characters and in the case of the measured value data sets M1, M2, M3 contains a measured glucose concentration value, which is in mg/dl alone. For the time correction data set T, the data field D contains a content value (entry) of '999', which indicates that the data set is a time correction data set.

The second data field B also has a length of four characters and in the case of the measured numerical data sets M1, M2, M3, which describe the time of day at which the measurement was taken, the first two characters are hours, from 0 to 24, and the last two characters are minutes, from 0 to 59. In the example of the time correction data set T, the data field B contains the magnitude by which the time is changed.

In the illustrated embodiment, the field D of the time correction data set T contains the number of minutes for which the time is adjusted, such that in the case of a time correction data set, the field B contains a content value between 0 and the maximum number of minutes (i.e., 1140) contained in 24 hours. Theoretically, the number of hours or minutes could be entered into each position of the data field bits of the time correction data set, in this example the first two characters of the data field bit B representing the number of hours the clock is adjusted, and the last two characters of the data field bit B representing the minute value by which the clock is adjusted in minute value.

In the embodiment of the time correction data set T shown, the clock of the hand-held device 1 is adjusted for 2 hours, so that the data field B shows the value of 0120, which means that the clock is adjusted for 120 minutes.

In the example of a measured value data set, the three data fields C of the data set show the date on which the measured value was obtained, the first two numbers being years, the next two numbers being months and the last two numbers being days. In the example of a time correction data set, the last two numbers may represent the number of days the clock is adjusted, while the two numbers preceding the last two numbers represent the number of months, and the first two numbers represent the number of years each part of the date is adjusted.

The fourth field of the data set of the embodiments discussed above contains different flags indicating whether the data fields B and C of the data set are positive or negative at a time, thereby indicating the direction in which the clock setting is changed. For example, character B in the D field of data set T is a flag indicating that the clock is being dialed back. Preferably, the field D additionally contains a check bit or a check code to let the data set check for possible write or read errors. In addition, field D may contain content values that indicate whether the measured value in each measured value data set is above or below a predetermined threshold value.

The data field bits of the measured value data set are described as a time field in the measured value data set and a time correction field in the time correction data set. The data field C is described as a date field in the measured data set of values and a date correction field in the time correction data set.

When the clock is set, it may happen that the amount by which the clock is adjusted cannot be determined. This situation can occur when the device is first used or after a long period of time without power (e.g., batteries replaced). In this case, the control unit writes a special data set (preferably of the same length and structure as the measured value data set and time correction data set) into the memory. The special data set may be distinguished from the time correction data set by a special flag set in the flag field D.

List of reference numerals

1: hand-held device

2: bearing belt

3: display mechanism

4: operating element

5: hardware interface

M1, M2, M3: measured value data set

T: time correction data set

A, B, C, D: data field bits (fields).

Claims (16)

1. A handheld device for measuring an analyte concentration in a bodily fluid sample, the handheld device comprising:

a display means (3) for displaying the measured value;

a measured value storage for storing measured values;

a measurement unit for generating a measured value by measurement of the analyte concentration in the body fluid sample;

a clock for providing the date and time of day;

a control unit for generating measured value data sets, each data set including the measured value provided by the measuring unit and a date and time of measurement used to obtain the measured value, and for writing the data sets into a memory of the measured value;

an operating element (4) which can be actuated by a user to set a clock, in which case the control unit will generate a set of time correction data (T) indicating the magnitude and direction in which the setting is carried out,

the control unit writes the time correction data sets (T) into the memory of the measured values, so that a chronologically ordered sequence comprising time correction data sets (T) and measured value data sets is generated.

2. The hand-held device according to claim 1, characterized in that the measured value data set and the time correction data set (T) have the same length.

3. The hand-held device according to claim 1, characterized in that the time correction data set (T) is identified as time correction data set (T) by a sign starting at the same position as the field containing the measured value at the start of the measured value data set in relation to the start of the data set (T).

4. A hand-held device according to claim 3, wherein the indicia of the time correction data set (T) have the same length as the field of the measured value data set containing the measured value.

5. The handheld device of claim 3 wherein the token begins with a bit string representing a character 9.

6. A hand-held device according to claim 3, characterised in that the symbol is arranged at the beginning of the time correction data set (T).

7. The hand-held device according to claim 1, wherein the measured value data set comprises a time field (B) showing the time of day the measurement was performed, and the time correction data set (T) comprises a time correction field (B) showing the number of minutes the time of day was changed by the clock setting operation at the position where the time field (B) was found in the measured value data set.

8. The hand-held device according to claim 1, wherein the measured value data set includes a date field (C) showing a date on which the measurement was performed, and the time correction data set (T) includes a date correction field (C) showing the number of days on which the date was changed by a clock setting operation at a position where the date field (C) was found in the measured value data set.

9. The hand-held device according to claim 1, wherein the time correction data set (T) comprises a flag field (D) indicating the set direction that is implemented.

10. The hand-held device of claim 9, wherein one flag in the flag field (D) shows the direction of the setting in minutes and another flag shows the direction of the setting in another time unit.

11. The hand-held device of claim 1, wherein the control unit writes a special data set into the memory when no reference time that can be changed by the setting operation is available while the clock is set and thus when a set magnitude and direction cannot be displayed.

12. The hand-held device according to claim 11, wherein a particular data set is distinguishable from the time correction data set (T) by a marker.

13. The hand-held device of claim 12, wherein the flag for distinguishing a particular dataset from time correction dataset (T) is set in the flag field.

14. The handheld apparatus of claim 10 wherein said another unit of time is a unit of days.

15. The hand-held device according to any one of claims 1 to 14, wherein the device is a blood glucose meter.

16. The hand-held device according to any of claims 1 to 14, wherein the device comprises a battery compartment.