Blood sugar analyzing apparatus

• US 4,407,959 A
• Filed: 10/21/1981
• Issued: 10/04/1983
• Est. Priority Date: 10/29/1980
• Status: Expired due to Fees

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Tsuji, Nobuhiko, Ishida, Keiichi, Endoh, Koichi, Nakamura, Keijiroh, Hamada, Toshiyoshi
• Primary Examiner(s): Marantz, Sidney
• Application Number:
  US06/313,666
• Time in Patent Office: 713 Days
• Field of Search: 422/81, 435/288, 435/289, 435/14, 435/291, 435/817, 204/195 B, 204/1 T, 364/415, 364/416, 364/497, 436/50, 436/55, 436/34
• US Class Current: 204/403.1
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode
• CPC Class Codes: Y10T 436/115831 Condition or time responsive

Abstract

A blood sugar analyzer system for measuring the blood sugar concentration level in a blood specimen is provided. A sensor having a fixed enzyme membrane and a measuring electrode generates a reaction current proportional to the blood sugar level of the specimen, and a sampling mechanism samples the sensor output at regular intervals. A memory receives data from the sampling and divides the data into a group of new data and a group of old data. A calculating mechanism calculates the average value of each group, and the difference between the averages. When the difference exceeds a predetermined value, the latest sensed data value is selected as the rising point of the chemical reaction between the fixed enzyme membrane of the sensor and the blood sugar of the specimen.

Claims

1. A blood sugar analyzing apparatus for analyzing the blood sugar concentration in a blood specimen, comprising:

a reaction cell which houses an enzyme membrane sensor including a fixed enzyme membrane and a measuring electrode, said cell having means for receiving a blood specimen in contact with said sensor to thereby cause a chemical reaction to occur between the specimen and the membrane, and wherein the measuring electrode produces a reaction current in response to the chemical reaction;

means for sampling an output from said sensor at given intervals of time;

means for storing data representing the sampled outputs;

processing means for separating the stored data into new and old data groups, for calculating the average data values of said new and old data groups and for calculating the difference between the average data values, and for determining a background offset portion of the reaction current at a first time point when said difference exceeds a first predetermined value and for determining a steady state level of the reaction current at a second time point, after said first time point, when the difference does not exceed a second predetermined value, and for calculating a blood sugar concentration level of the specimen which is proportional to the difference between the steady state level and the background offset portion of the reaction current.

2. A blood sugar analyzing apparatus for analyzing the blood sugar concentration in a blood specimen, comprising:

a reaction cell which houses a fixed enzyme membrane and a measuring electrode, said cell having means for receiving a blood specimen to thereby cause a chemical reaction between said blood specimen and said fixed enzyme membrane for measuring the blood sugar concentration in said blood specimen on the basis of a reaction current generated in said measuring electrode by the chemical reaction, said reaction cell also having means for receiving a buffer liquid supplied each time said chemical reaction is terminated so as to be washed thereby; and

control means for detecting a rising point of said reaction current when said blood specimen is introduced into said reaction cell, for storing the current level from the measuring electrode at that time, for detecting when the reaction has terminated, for supplying said buffer liquid to said cell after the reaction has been terminated, and for stopping the supply of said buffer liquid when said reaction current level returns to the level of said rising point.

3. A blood sugar analyzing apparatus for analyzing the blood sugar in a blood specimen, comprising:

a reaction cell which houses an enzyme membrane sensor including a fixed enzyme membrane and a measuring electrode, said cell also having means for receiving a blood specimen in contact with said sensor to thereby cause a reaction current to be generated in the measuring electrode in response to a chemical reaction between the specimen and membrane;

means for determining the rising point of the reaction and for determining a background offset portion of the reaction current at a first time point;

means for determining a steady state value of the reaction current at a second time point, after said first time point; and

means for calculating a blood sugar concentration level of said specimen which is proportional to the difference between said steady state value and said background offset value.