Total Bilirubin

Function

Total Bilirubin is a measurement of the sum of conjugated (direct) and unconjugated (indirect) bilirubin in the blood. Bilirubin is a yellowish pigment formed during the normal breakdown of red blood cells. It travels through the bloodstream to the liver, where it is processed (conjugated) and excreted into bile. This test is a primary indicator of how well the liver is functioning and whether the bile ducts are clear.

Why it is Ordered

Total bilirubin is a standard component of a Liver Function Test (LFT) panel. It is ordered to investigate jaundice (yellowing of the skin and eyes), monitor the progression of liver diseases like hepatitis or cirrhosis, and evaluate potential gallstones or bile duct obstructions. In newborns, it is used to monitor neonatal jaundice and prevent brain damage (kernicterus).

Associated Conditions

• Hepatitis: Viral or toxic inflammation of the liver.
• Cirrhosis: Long-term scarring of liver tissue.
• Gilbert’s Syndrome: A common, harmless genetic condition where the liver doesn't process bilirubin properly.
• Hemolysis: Conditions that cause rapid RBC destruction (e.g., sickle cell, G6PD deficiency).
• Choledocholithiasis: Gallstones blocking the common bile duct.

Interpretation with Fractions

While 'Total' bilirubin gives a baseline, if it is high, doctors will usually 'fractionate' it to see if the elevation is 'indirect' (suggesting blood breakdown or liver processing issues) or 'direct' (suggesting a physical blockage in the bile ducts).