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Laboratory: Clinical Biochemistry  (AUTOMATED)
Test Name:
Test Code: TB
Clinical Information:
Description: Bilirubin is an orange-yellow pigment formed from hemoglobin during the degradation of red blood cells. It is bound to albumin and transported to the liver where it is conjugated with glucuronic acid for solubilization and subsequent elimination by the digestive tract.
Levels of unconjugated bilirubin are increased if it is produced faster than it can be metabolized by the liver. Liver immaturity or other disorders of liver bilirubin conjugation will cause elevations in circulating unconjugated bilirubin. Bile duct obstruction or liver damage causes increases in both conjugated and unconjugated bilirubin.
Bilirubin testing is used to assess liver function and evaluate disorders of bilirubin metabolism. It is also used to monitor the effect of neonatal phototherapy.

Guidelines for Detection, Management and Prevention of Hyperbilirubinemia in Term and Late Preterm Newborn Infants. Pediatr Child Healh 2007, 12(suppl B): 1B-12B

See entry Bilirubin, Direct - (P) for information on reflex testing to Bilirubin, Direct for infants 14 days to 6 months of age 
Collection Devices:
Specimen Required:

Plasma: 2.0 mL
Pediatric Plasma: 0.2 mL

Specimens are stable in normal laboratory conditions for up to 8 hours if kept in original labelled collection tubes. Specimens are not suitable for analysis if time of collection to testing exceeds 8 hours and they have not been protected from light.
Stability 7 days refrigerated, 6 months frozen if protected from light by storing in an amber tube or wrapping in foil.
Serum: 2.0 mL

Samples must be transferred to an aliquot tube and stored frozen if analysis will not be complete within 48 hours (#110-10-05 Serum / Plasma Separation Procedure & Transport). Specimens must be protected from light by storing in an amber tube or wrapping in foil.
Reference Values:
Cord Blood:       < 34           μmol/L                       
< 1 d: 24 - 149
1 - 2 d: 58 - 197
3 - 5 d: 26 - 205
6 d - 60 y:    5 - 21
61 - 90 y:    3 - 19
> 90 y:    3 - 15
(μmol/L x 0.06 = mg/dL)
Stat or Routine
See Also:
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