Test Details

• Discipline:

  Biochemistry

  Biochemistry

• Specimen Container Adult:

  Serum (SST or plain tube)

  Serum (SST or plain tube)

• Specimen Container Paediatric:

  Serum (SST or plain tube)

  Serum (SST or plain tube)

• Minimum Volume Adult:

  1 mL blood

  1 mL blood

• Minimum Volume Paediatric:

  0.5 mL blood

  0.5 mL blood

• Sample Stability:

  Unseparated: day of collection

  Separated: day of collection at room temperature, 7 days at 4ºC, 6 months at -20C

  Unseparated: day of collection

  Separated: day of collection at room temperature, 7 days at 4ºC, 6 months at -20C

• Interpretation:

  1. Increased production of bilirubin may exceed the ability of the liver to conjugate and excrete the pigment, causing an increase in the plasma
  [unconjugated bilirubin]. However, the capacity of ...

  1. Increased production of bilirubin may exceed the ability of the liver to conjugate and excrete the pigment, causing an increase in the plasma
  [unconjugated bilirubin]. However, the capacity of the liver to process bilirubin exceeds the normal rate of production, so that increased production does not necessarily cause hyperbilirubinaemia.

  Specific causes include:
  • haemolysis (autoimmune, congenital and other haemolytic anaemias)
  • ineffective erythropoesis
  • rhabdomyolysis (because of increased breakdown of myoglobin).
  2. Decreased hepatic uptake can be caused by several drugs, e.g. rifampicin. Although bilirubin uptake may be decreased in hepatocellular disease, the excess bilirubin in the plasma is primarily conjugated, reflecting decreased secretion into the biliary system.
  3. The conjugation of bilirubin may also be impaired in hepatocellular disease, but any excess bilirubin in the plasma is primarily conjugated. Two inherited conditions of impaired bilirubin conjugation can cause unconjugated hyperbilirubinaemia.

  These are:-
  • Gilbert’s syndrome (common and benign) typically causing only mild hyperbilirubinaemia (≤100 µmol/L) and sporadic jaundice, typically
  in young adults
  • Crigler‐Najjar syndromes types I and II, causing severe hyperbilirubinaemia and typically presenting in infancy.
  4. Impaired secretion of bilirubin into the biliary system can occur in hepatocellular diseases. It can also be caused by drugs, including chlorpromazine, carbamazepine and erythromycin. Impaired secretion bilirubin into the biliary system is a feature of two rare inherited disorders, Rotor syndrome and Dubin‐Johnson syndrome.
  5. Biliary obstruction can cause diffusion of conjugated bilirubin from the biliary system into the bloodstream. Such obstruction can be intrahepatic
  (e.g. cirrhosis) or extrahepatic (e.g. sclerosing cholangitis, carcinoma of the head of the pancreas, causing obstruction through external pressure on the common bile duct.

  Read More

• Reference Ranges:

  Up to and including 14 days: 0 – 150 umol/L

  Over 14 days: 0 – 21 umol/L 

  Up to and including 14 days: 0 – 150 umol/L

  Over 14 days: 0 – 21 umol/L 

• Other Info:

  lithium heparin plasma sample also acceptable

  lithium heparin plasma sample also acceptable

• Routine Contact Name:

  Duty Biochemist

• Routine Telephone:

  Freeman: 0191 244 8889
  RVI: 0191 282 9719

  Freeman: 0191 244 8889
  RVI: 0191 282 9719

• Routine Email:

  nuth.dutybiochemist@nhs.net