Bilirubin Total and Direct Blood Test

What is the purpose of this test?

If you suspect a liver or red blood cell disorder, you can order the Bilirubin Total & Direct Blood Test to measure the bilirubin levels in your blood. Bilirubin is a dark yellow waste product the body produces when it breaks down old red blood cells. It's mainly found in bile, a fluid created in the liver, and is stored in the gallbladder. It's involved in the digestive process and is eliminated from the body through feces or urine.

There are two forms of bilirubin in the blood: unconjugated and conjugated. Initially, bilirubin is attached to albumin, the main protein in blood that carries substances to the liver, making it water-insoluble. In the liver, bilirubin undergoes a process called conjugation with a substance called glucuronide, making it water-soluble and ready to be excreted into the bile. A total blood test includes both unconjugated (indirect) and conjugated (direct) bilirubin measurements. Unconjugated bilirubin may also be called indirect bilirubin (total bilirubin minus direct bilirubin), and conjugated bilirubin may be called direct bilirubin (directly measured).

When should I order a Bilirubin Total & Direct Blood Test?

Individuals may order this test if they have experienced symptoms of the following conditions:

• Jaundice
• Hepatitis
• Cirrhosis
• Gallbladder disease
• Hemolytic anemia

Healthcare providers may use bilirubin blood testing to help diagnose these conditions. This test is also used to diagnose newborn jaundice, which can lead to kernicterus at extremely high bilirubin levels. Newborns are commonly tested during their first few days of life and when jaundice symptoms show. Repeated bilirubin testing can help doctors monitor the status of the disease and the response to treatment if a patient has been diagnosed with a liver disorder.