In radioimmunoassays and radioassays for various constituents of serum, color quenching is a source of error when liquid-scintillation methods are used in samples that contain hemolyzed blood and samples from jaundiced patients. A quench correction can be made by using the External Standard Channels Ratio method and normalizing the ratios, or, alternatively, by chemical decolorization with tetramethylammonium hydroxide, hydrogen peroxide, and ascorbic acid.