A Direct Bilirubin test measures the level of direct (conjugated) bilirubin in the blood. Bilirubin is a yellow pigment produced during the normal breakdown of red blood cells. It exists in two forms: indirect (unconjugated) bilirubin, which is processed by the liver, and direct (conjugated) bilirubin, which has been processed by the liver and is ready to be excreted into bile.
This test is commonly used to evaluate liver function and to help diagnose liver and bile duct disorders. Elevated direct bilirubin levels typically suggest a problem with bile flow out of the liver, such as bile duct obstruction, liver disease (hepatitis, cirrhosis), or gallstones. It is often ordered as part of a Liver Function Test (LFT) panel alongside total bilirubin, ALT, AST, and ALP.
