Methods of determining initiation and variable end points for measuring a chemical reaction
First Claim
1. A method of using a reflectance-reading device to determine an initiation time point for measuring a chemical reaction of an analyte from a biological liquid sample on a test surface, comprising the steps of(a) using a device to read a reflectance R of a test surface at a plurality of time points,(b) calculating a K/S ratio of the test surface at each time point according to an equation
(c) monitoring a rate of change of the K/S ratio with respect to time, and(d) determining an initiation time point for measuring a chemical reaction when the rate of change of the K/S ratio is maximal.
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Abstract
The present invention provides a method of using a reflectance-reading device to determine an initiation time point for measuring the chemical reaction of an analyte from a biological liquid sample on a test surface. The initiation time point is determined by using a device to read a reflectance of a test surface at a plurality of time points, and calculating the K/S ratio of the test surface at each time point according to the Kubelka-Munk equation. As the device continues to calculate a K/S ratio for each time point, the device monitors the rate of change of the K/S ratio with respect to time. The device then determines the initiation time point to be when the rate of change of the K/S ratio is maximal. The present invention also provides a method of measuring the concentration of an analyte on a test surface. The concentration is measured by determining an initiation time point according to the method described above and then measuring the concentration of the analyte at a variable end point. The variable end point is essentially determined to be the time at which the rate of change of a concentration parameter is less than a threshold value.
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16 Claims
- 1. A method of using a reflectance-reading device to determine an initiation time point for measuring a chemical reaction of an analyte from a biological liquid sample on a test surface, comprising the steps of
(a) using a device to read a reflectance R of a test surface at a plurality of time points, (b) calculating a K/S ratio of the test surface at each time point according to an equation - space="preserve" listing-type="equation">K/S=(1-R).sup.2 /2R
(c) monitoring a rate of change of the K/S ratio with respect to time, and (d) determining an initiation time point for measuring a chemical reaction when the rate of change of the K/S ratio is maximal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
Specification