Sign of abnormal liver function.

Emobileclinic Trending Topic: Bilirubin

A bilirubin test is used to detect an increased level in the blood. It may be used to help determine the cause of jaundice and/or help diagnose conditions such as liver disease, hemolytic anemia, and blockage of the bile ducts. It is an orange-yellow pigment, a waste product primarily produced by the normal breakdown of heme. It is ultimately processed by the liver to allow its elimination from the body. Any condition that accelerates the breakdown of RBCs or affects the processing and elimination of bilirubin may cause an elevated blood level.

Two forms of bilirubin can be measured or estimated by laboratory tests:

Unconjugated bilirubin—when heme is released from hemoglobin, it is converted to unconjugated bilirubin. It is carried by proteins to the liver. Small amounts may be present in the blood.

Conjugated bilirubin—formed in the liver when sugars are attached (conjugated) to bilirubin. It enters the bile and passes from the liver to the small intestines and is eventually eliminated in the stool. Normally, no conjugated bilirubin is present in the blood.

In adults and older children, bilirubin is measured to:

Diagnose and/or monitor diseases of the liver and bile duct (e.g., cirrhosis , hepatitis , or gallstones)

Evaluate people with sickle cell disease or other causes of hemolytic anemia; these people may have episodes called crises when excessive RBC destruction increases bilirubin levels.

In newborns with jaundice, bilirubin is used to distinguish the causes of jaundice.

It is important that an elevated level of bilirubin in a newborn be identified and quickly treated because excessive unconjugated bilirubin damages developing brain cells. The consequences of this damage include mental retardation, learning and developmental disabilities, hearing loss, eye movement problems, and death.

When is it requested?

A health practitioner usually requests for a  bilirubin test in conjunction with other laboratory tests (alkaline phosphatase , aspartate aminotransferase , alanine aminotransferase) when there is:

Sign of abnormal liver function. 

Evidence of jaundice

History of excessive intake of alcohol

Drug toxicity

Exposed to hepatitis-causing viruses

Symptoms

Dark, amber-colored urine

Nausea/vomiting

Abdominal pain and/or swelling

Fatigue and general malaise that often accompany chronic liver disease

Implications of the result?

In both adults and children, an increased total bilirubin that is mainly unconjugated (indirect) bilirubin may be a result of:

Hemolytic or pernicious anemia

Transfusion reaction

Cirrhosis

If conjugated (direct) bilirubin is elevated more than unconjugated (indirect) bilirubin, there typically is a problem associated with decreased elimination of bilirubin by the liver cells. Some conditions that may cause this include:

Viral hepatitis

Drug reactions

Alcoholic liver disease

Drugs that can decrease total bilirubin include barbiturates, caffeine, penicillin, and high doses of salicylates. The drug atazanavir increases unconjugated (indirect) bilirubin.