Bilirubin, direct

Alphabetical Test listing

Bilirubin, direct-47

  
Bilirubin, direct
  
47
  
82248.0
  
BID
  
Bili
  

Direct bilirubin is the sum of the conjugated fractions. Direct bilirubin is elevated in conditions causing hepatic obstruction, hepatitis, cirrhosis, several inherited enzyme deficiencies, and inherited defects in canalicular excretion.

  
Lithium heparin (Li hep) plasma
  
  
1.0 mL
  
0.2 mL
  

Spin

Protect specimen from bright light as bilirubin is photolabile. Exposure to direct sunlight can decrease bilirubin in samples by 50% within one hour.

  
  

Gold - Spin

Dk green/lavender - Spin and separate

  

Gold serum separator (SST) tube, or

Transfer vial/tube with cap - 12mL (LabCorp)

  

Refrigerated (preferred) - 7 days

Ambient - 2 days

  
  • Improper labels (unlabeled or mislabeled)
  • Hemolysis (some procedures)
  • Improper anticoagulant or ratio
  • Delay in transport
  • Improper storage temperature affecting results
  • Improper container
  • Leaking container resulting in compromised specimen
  • Quantity not sufficient (QNS)
  
AHL - Chemistry: C
  
Daily
  
1 day
  

Endpoint Colorimetric with Diazo

  

Adult: 0.1 - 0.5 mg/dL

  

Red blood cells at the end of their circulating life are broken down in the reticuloendothelial system, mainly the spleen. The resulting heme, once the iron is removed, is then converted to bilirubin. This process accounts for about 80% of the 500 μmol (300 mg) of bilirubin formed daily. Other sources of bilirubin include the breakdown of myoglobin and cytochromes and the catabolism of immature red blood cells in the bone marrow.

Once formed, bilirubin is transported to the liver bound to albumin. This fraction of bilirubin is referred to as indirect or unconjugated bilirubin. In the liver, bilirubin is conjugated to glucuronic acid (mono- and di-glucuronides) to form conjugated bilirubin by the enzyme uridyl diphosphate glucuronyl transferase. Conjugated bilirubin or direct bilirubin is excreted via the biliary system into the intestine, where it is metabolized by bacteria to a group of products known collectively as stercobilinogen. Elimination is almost complete and serum levels are normally negligible.

Direct bilirubin is the sum of the conjugated fractions. Direct bilirubin is elevated in conditions causing hepatic obstruction, hepatitis, cirrhosis, several inherited enzyme deficiencies, and inherited defects in canalicular excretion.

  
82248
  
11/30/2001
  
02/18/2020
  
02/07/2020