What is the proper handling of a bilirubin sample?

Bilirubin is a light-sensitive compound, and its concentration in a blood sample will degrade rapidly if the specimen is exposed to light. Therefore, bilirubin samples must be protected from light by wrapping the tube in foil or placing it in an amber-colored container immediately after collection, and transporting it promptly to the laboratory. This photodegradation occurs because light causes a photoisomerization reaction that converts bilirubin to lumirubin and other byproducts, falsely lowering measured bilirubin levels and potentially leading to undertreatment of neonatal jaundice. Minimizing heat exposure is a general principle for many specimens but is not the primary concern specific to bilirubin. Placing the sample in a clear biohazard bag would not protect it from light and is contraindicated for this test. Using a lavender tube is incorrect because bilirubin is typically collected in a gold or red-top serum tube, not an EDTA lavender tube. Students should associate light protection specifically with bilirubin and also with other photosensitive analytes such as beta-carotene and folate, understanding that failure to protect the sample will produce falsely low results.