Pathology Handbook

Bilirubin

Synonyms

Total Bilirubin

Clinical Indications

Bilirubin is derived from haem and transported to the liver bound mainly to albumin (unconjugated bilirubin). In the liver bilirubin is conjugated with glucuronic acid (conjugated bilirubin) which makes it water soluble and is excreted in bile.

Serum bilirubin levels are a balance between production and clearance. The liver has a large capacity for conjugation of bilirubin. Bilirubin is therefore a relatively insensitive test of liver disease. Increased levels of conjugated bilirubin are seen in cholestasis. Gilberts syndrome is a common cause of isolated hyperbilirubinaemia due to increased unconjugated bilirubin.

Most common chronic haemolytic disorders present with mild unconjugated hyperbilirubinaemia. In adults, quantitation of conjugated bilirubin is seldom necessary unless intra-vascular haemolysis is suspected. However, measurement of conjugated bilirubin is important in assessment of neonatal jaundice.

Part of Profile

Liver Function Test

Request Form

Request on ICE

Availability

On request

Specific Criteria

None

Turnaround Time

Same day

Specimen

Serum in gold-top vacutainer

Volume

2 ml

Container

Vacutainer gold top

Causes for Rejection

Unlabelled or incorrectly labelled sample;

Reference Range

Total Bilirubin: <21 umol/L