Some specimens routinely collected for testing by using a capillary puncture are adversely affected by exposure to light. One example is a specimen collected for bilirubin testing that is obtained from a newborn. When obtaining the specimen for this testing, it is important for the phlebotomist to recognize the effect of light on the specimen. Room light or sunlight can metabolize the bilirubin in the specimen to a different compound. This will cause a falsely lower bilirubin level. A neonatal bilirubin specimen should be obtained in a dark-colored (amber) container. Alternately, a clear or white container can be immediately wrapped in aluminum foil following the blood collection, preventing the blood from exposure to light.