Ciulla Clinical Chemistry Practice Test 2026 - Free Clinical Chemistry Practice Questions and Study Guide

Bilirubin measurement depends on the sample’s optical properties and the chemical stability of bilirubin, so anything that alters light transmission or degrades bilirubin can bias the result. Lipemia makes the serum turbid, scattering light and changing absorbance in the measurement, which can falsely skew bilirubin readings. Hemolysis releases pigments and cellular components that interfere with the colorimetric or spectrophotometric assay, again distorting the result. Prolonged light exposure degrades bilirubin through photolysis, producing degradation products that falsely lower the measured level. In contrast, refrigerating the specimen helps preserve bilirubin until analysis, slowing degradation and maintaining stability, so it does not introduce error.