Laboratory: Clinical Biochemistry  (AUTOMATED)
Test Name:
Test Code: DB
Clinical Information:
The direct bilirubin assay detects water-soluble forms of bilirubin and provides an estimate of the amount of conjugated bilirubin present.
Conjugated bilirubin is formed in the liver when sugars are attached (conjugated) to bilirubin. It enters the bile and passes from the liver to small intestine and is eventually eliminated in the stool. Normally, only low concentrations of conjugated bilirubin are present in the blood.
For infants 30 days to 3 months of age, if total bilirubin (TBIL) is >20 µmol/L, the lab will automatically add and report a direct (conjugated) bilirubin (DBIL). If the DBIL is >20% of the the TBIL, and the DBIL is >17 µmol/L the lab will add a comment to the DBIL report: "Elevation in conjugated (direct) bilirubin level is pathologic. Prompt evaluation is necessary for neonatal cholestasis including biliary atresia. Please consider discussing with pediatric gastroenterologist or pediatrician on service (HSC paging 204-787-2071)."
For infants less than 30 days of age, or individuals >3 months of age, only the ordered bilirubin tests will be performed. The lab will not perform DBIL testing unless it is ordered (no reflex testing from TBIL).
Pediatric Guidelines: Guidelines for Detection, Management and Prevention of Hyperbilirubinemia in Term and Late Preterm Newborn Infants. Pediatr Child Health 2007, 12(suppl B): 1B-12B
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:
< 7.0 μmol/L             (μmol/L x 0.06 = mg/dL)
Stat or Routine
See Also:
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