Method for analyzing a component of a liquid sample

Abstract

A method and apparatus for analyzing a component of a liquid sample performs the analysis in a number of steps. A test-strip analyzer is provided, which includes a test-strip, a code substrate, and a valuation device. The test-strip includes reagents, and the component of the liquid sample reacts with the reagents. The reaction results in a physically detectable change. The method includes the steps of initiating a relative motion between the code substrate and an optical-electrical transducer of the valuation device, and generating a binary signal in the analyzer. The binary signal is generated as a result of the relative motion, and contains information of the valuation code and the optical transducer during the motion scanning at least one track of the analytical code. An output voltage is generated from detected brightness values, and maximum and minimum peak voltages are ascertained when reading a bright zone and a dark zone, respectively. A first and second comparison voltages are generated, with the first comparison voltage being less by a first amount than a maximum peak voltage value, and the second comparison voltage being larger by a second amount than the minimum peak voltage value. The output voltage of the transducer is compared with the first and second comparison voltages. The minimum peak voltage value is reset to a higher voltage value when the output voltage drops below the first comparison voltage, and the maximum peak voltage value is reset to a lower peak voltage value when the output voltage rises above the second comparison voltage.