Binary kinetic assay method and apparatus

A method for providing an indication that a reaction between a sample containing at least a first analyte and a reagent is influenced by the presence of at least a second analyte in the sample also reacting with the reagent but at a rate different from the first analyte comprising the steps of:

• performing a first reaction with only the first analyte and the reagent, selecting first and second times for reaction rate measurements such that one of such times corresponds substantially to a time that the reaction rate of the first analyte reaches a peak during the first reaction, measuring first and second reaction rates at the first and second times, respectively, during the first reaction and forming a first ratio between the first and second reaction rates;
• performing a second reaction with the sample and the reagent, measuring third and fourth reaction rates at the first and second times, respectively, during the second reaction, and forming a second ratio between the third and fourth reaction rates;
• and
• comparing the first ratio and the second ratio and providing the indication if the second ratio differs from the first ratio by a predetermined amount.

An apparatus for providing an indication that a reaction between a sample containing at least a first analyte and a reagent is influenced by the presence of at least a second analyte in the sample also reacting with the reagent but at a rate different from the first analyte comprising:

• means for performing a first reaction with only a first analyte and a reagent;
• means for measuring first and second reaction rates at respective first and second times during the first reaction;
• means for forming a first ratio between the first and second reaction rates;
• means for performing a second reaction with a sample and the reagent;
• means for measuring third and fourth reaction rates at the first and second times, respectively, during the second reaction;
• means for forming a second ratio between the third and fourth reaction rates;
• means for comparing the first ratio and the second ratio;
• and
• means for providing the indication if the second ratio is in a predetermined relationship with the first ratio.

An apparatus for providing an indication that a reaction between a sample containing at least a first analyte and a reagent is influenced by the presence of at least a second analyte in the sample also reacting with the reagent but at a rate different from the first analyte comprising:

• means for performing a first reaction with only a first analyte and a reagent;
• means for fixing first and second times for reaction rate measurements such that one of such times corresponds substantially to a time that the reaction rate of the first analyte reaches a peak during the first reaction;
• means for measuring first and second reaction rates at the first and second times, respectively, during the first reaction;
• means for forming a first ratio between the first and second reaction rates;
• means for performing a second reaction with a sample and the reagent;
• means for measuring third and fourth reaction rates at the first and second times, respectively, during the second reaction;
• means for forming a second ratio between the third and fourth reaction rates;
• means for comparing the first ratio and the second ratio;
• and
• means for providing the indication if the second ratio differs from the first ratio by a predetermined amount.