Method for determining the glucose content of a blood sample
First Claim
1. An apparatus for determining a chemical component from a sample of matter, the apparatus comprising:
- a sample holder for accommodating a test strip, the test strip being configured to receive the sample on one side of the test strip, the test strip including a reagent, the reagent being configured to cause a color reaction, directly or through an intermediate reaction, with the chemical component, and the test strip being further configured such that components of the sample penetrate the test strip and start the color reaction at an opposing side of the test strip;
a light source for illuminating the sample placed into the sample holder;
a measuring circuit for measuring the intensity of the light reflected from the sample and generating an output signal corresponding to the intensity of the light;
a controller and analyzer circuit for receiving the output signal from the measuring circuit, where the controller and analyzer circuit is configured to determine the chemical component of the sample by;
illuminating the sample and measuring a reflection R from the test strip and recording a reflection function R(t), detecting a wetting through of the sample, determining a starting time T0, where the starting time T0 is not earlier than the time of detection of wetting through of the sample, generating from the starting time T0, a function R(t)+L(t), where L(t) is a predetermined function that is independent of the measured reflection, monitoring and storing an extreme value ext[R(t)+l(T)] of the R(t)+L(t) function, generating a function R(t)+L(t)−
ext[R(t)+L(t)] from the time of reaching at least one value for extreme value ext[R(t)+L(t)], where the R(t)+L(t)−
ext[R(t)+L(t)] function reaches a predetermined C(t) value, determining a Tm measuring time, C(t) being a predetermined function independent of the measured reflection, and determining from the R reflection value measured at the Tm measuring time an amount of the chemical component in the sample.
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Abstract
The invention relates to a method and apparatus for determining a chemical component from a sample, where the sample is measured on a test strip with the help of a color reaction. The method concerns finding the measurement time Tm for measuring the reflection of the test strip. The method comprises the following steps: a) Recording the R(t) function, b) Determining the T0 starting time at the detection of the wetting through of the sample, c) Generating the function R(t)+L(t), d) Monitoring and storing the ext[R(t)+L(t)] extreme value of the R(t)+L(t) function, and, at the same time, e) Generating the function R(t)+L(t)−ext[R(t)+L(t)] from the time of reaching an ext[R(t)+L(t)] extreme value, f) when the R(t)+L(t)−ext[R(t)+L(t)] function reaches a predetermined C(t) value, determining the Tm measuring time.
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Citations
25 Claims
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1. An apparatus for determining a chemical component from a sample of matter, the apparatus comprising:
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a sample holder for accommodating a test strip, the test strip being configured to receive the sample on one side of the test strip, the test strip including a reagent, the reagent being configured to cause a color reaction, directly or through an intermediate reaction, with the chemical component, and the test strip being further configured such that components of the sample penetrate the test strip and start the color reaction at an opposing side of the test strip;
a light source for illuminating the sample placed into the sample holder;
a measuring circuit for measuring the intensity of the light reflected from the sample and generating an output signal corresponding to the intensity of the light;
a controller and analyzer circuit for receiving the output signal from the measuring circuit, where the controller and analyzer circuit is configured to determine the chemical component of the sample by;
illuminating the sample and measuring a reflection R from the test strip and recording a reflection function R(t), detecting a wetting through of the sample, determining a starting time T0, where the starting time T0 is not earlier than the time of detection of wetting through of the sample, generating from the starting time T0, a function R(t)+L(t), where L(t) is a predetermined function that is independent of the measured reflection, monitoring and storing an extreme value ext[R(t)+l(T)] of the R(t)+L(t) function, generating a function R(t)+L(t)−
ext[R(t)+L(t)] from the time of reaching at least one value for extreme value ext[R(t)+L(t)],where the R(t)+L(t)−
ext[R(t)+L(t)] function reaches a predetermined C(t) value, determining a Tm measuring time, C(t) being a predetermined function independent of the measured reflection, anddetermining from the R reflection value measured at the Tm measuring time an amount of the chemical component in the sample. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for determining a chemical component from a sample of matter, the apparatus comprising:
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means for accommodating a test strip, the test strip being configured to receive the sample on a reagent, the reagent being positioned on one side of the test strip, the reagent being configured to cause a color reaction, directly or through an intermediate reaction, with the chemical component to be measured, and the test strip being configured so that components of the sample penetrate the test strip and start the color reaction at the other side of the test strip; and
means for measuring a content amount of a component in the sample through optical reflection measurement of the resulting color reaction by illuminating the sample and measuring at discrete time intervals or substantially continuously a reflection R on the test strip and recording a function R(t);
means for detecting a wetting through of the sample in order to determine a starting time T0, where T0 is not earlier than the time of detection of wetting through;
means for generating from the T0 starting time a function R(t)+L(t), where L(t) is a predetermined function that is independent of the measured reflection;
means for monitoring and storing an extreme value ext[R(t) +L(t)] of the R(t)+L(t) function;
means for generating a function R(t)+L(t)−
ext[R(t)+L(t)] from a time of reaching at least one extreme value ext[R(t)+L(t)];
means for determining a Tm measuring time when the R(t)+L(t)−
ext[R(t)+L(t)] function reaches a predetermined C(t) value; and
means for determining the content of the chemical component in the sample by comparing the R reflection value measured at the Tm measuring time to a predetermined calibrated measurement. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A system for determining a chemical component from a sample of matter, the system comprising:
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means for illuminating the sample and measuring a reflection R from a test strip and recording a reflection function R(t);
means for detecting a wetting through of the sample when the sample has been provided on the test strip;
means for determining a starting time T0, where the starting time T0 is not earlier than the time of detection of wetting through of the sample;
means for generating from T0 starting time a function R(t)+L(t), where L(t) is a predetermined function that is independent of the measured reflection;
means for monitoring and storing an extreme value ext[R(t)+L(t)] of the R(t)+L(t) function;
means for generating a function R(t)+L(t)−
ext[R(t)+L(t)] from the time of reaching at least one value for extreme value ext[R(t)+L(t)];
means for determining a Tm measuring time when the R(t)+L(t)−
ext[R(t)+L(t)] function reaches a predetermined C(t) value, L(t) and C(t) being predetermined functions independent of the measured reflection; and
means for determining from the R reflection value measured at the Tm measuring time an amount of the chemical component in the sample. - View Dependent Claims (22, 23, 24, 25)
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Specification