Clinical
Indications |
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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 (information
of laboratory investigation available).
Most common chronic haemolytic disorderspresent 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.
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