CLIA analyzer are automated instrument designed to perform chemiluminescent immunoassays with high sensitivity and precision. These systems combine the specificity of antigen–antibody reactions with chemiluminescent detection technology, where emitted light is measured using a photomultiplier tube (PMT) to ensure accurate quantification of a wide range of clinically important biomarkers. The use of PMT-based optics allows for highly sensitive detection of even very low analyte concentrations, producing reliable results.