The Chexel® measurement system relies on an immunofluorescent method to measure the analyte (troponin I) in human blood. The test is automatically performed by inserting a cartridge into the immunofluorescent device, injecting a sample, and pressing the scan button. The Chexel® measuring cartridge consists of a sample injection port and a signal detection window for detecting signals generated by antigen-antibody interaction. The reaction test paper in the cartridge contains troponin I-specific fluorophore-antibody conjugate and capture antibody. These molecules react with troponin I and generate signals proportional to the troponin I concentration in the sample. A sample (whole blood, plasma, serum) is loaded through the sample injection port at one end of the cartridge, and then the cartridge is placed on the tray on the immunofluorescence device. Pressing the scan button moves the tray into the device. Once the reaction is completed, the fluorophores on the signal emission region are excited by the laser diode, and the resulting fluorescence intensity is detected and measured by the sensor to determine the troponin I level in the sample. The measured fluorescence intensity value is converted and reported in concentration.