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Bilirubin, Direct

Mnemonic:    [Bili Dir]
Name:    Bilirubin, Direct
Specimen:    1 mL serum from a Red SST or Red top tube, or plasma from a Green PST.
Minimum Spec:    0.7 mL
Reference Range:    0.0 - 0.4 mg/dL
  Method:    Colorimetric
Note:    Derived from Total Bili - Bu fraction = Direct Bilirubin. Direct Bilirubin is the sum of conjugated bilirugin (Bc) and delta bilirubin (DELB). The value for direct bilirubin, as reported by the Vitros System, includes all bilirubin fractions that react in the Jendrassik-Grof reaction without the addition of promoters. These include the conjugated (mono and diconjugates) and delta bilirubins. Total Bilirubin is measured in the TBIL slide as the diazo derivitave of unconjugated Bu, conjugated, and covalently bound "delta" bilirubins. Conjugated and unconjugated bilirubins are measured simultaneously on the BuBc slide using a dual wavelength spectral measurement. Direct bilirubin values are calculated on the analyzer from these measured results.