Test ID: BILID Bilirubin Direct, Serum
Reporting Name
Bilirubin, DirectUseful For
Evaluation of jaundice and liver functions
Specimen Type
SerumShipping Instructions
Ship specimen in amber vial to protect from light.
Necessary Information
Patient's age and sex are required.
Specimen Required
Supplies: Amber Frosted Tube, 5 mL (T915)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Amber vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Serum gel tubes should be centrifuged within 2 hours of collection.
2. Red-top tubes should be centrifuged, and the serum aliquoted into an amber vial within 2 hours of collection.
Specimen Minimum Volume
0.25 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 24 hours | LIGHT PROTECTED |
Frozen | 30 days | LIGHT PROTECTED | |
Ambient | 6 hours | LIGHT PROTECTED |
Reference Values
≥12 months: 0.0-0.3 mg/dL
Reference values have not been established for patients who are <12 months of age.
Day(s) Performed
Monday through Sunday
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
82248
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
BILID | Bilirubin, Direct | 1968-7 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
BILID | Bilirubin, Direct | 1968-7 |
Clinical Information
Approximately 85% of the total bilirubin produced is derived from the heme moiety of hemoglobin while the remaining 15% is produced from the RBC precursors destroyed in the bone marrow and from the catabolism of other heme-containing proteins. After production in peripheral tissues, bilirubin is rapidly taken up by hepatocytes where it is conjugated with glucuronic acid to produce mono- and diglucuronide, which are excreted in the bile. Direct bilirubin is a measurement of conjugated bilirubin.
Jaundice can occur as a result of problems at each step in the metabolic pathway. Disorders may be classified as those due to: increased bilirubin production (eg, hemolysis and ineffective erythropoiesis), decreased bilirubin excretion (eg, obstruction and hepatitis), and abnormal bilirubin metabolism (eg, hereditary and neonatal jaundice).
Inherited disorders in which direct bilirubinemia occurs include Dubin-Johnson syndrome and Rotor syndrome. Jaundice of the newborn where direct bilirubin is elevated includes idiopathic neonatal hepatitis and biliary atresia. The most commonly occurring form of jaundice of the newborn, physiological jaundice, results in unconjugated (indirect) hyperbilirubinemia. Elevated unconjugated bilirubin in the neonatal period may result in brain damage (kernicterus). Treatment options are phototherapy and, if severe, exchange transfusion.
The increased production of bilirubin that accompanies the premature breakdown of erythrocytes and ineffective erythropoiesis results in hyperbilirubinemia in the absence of any liver abnormality. In hepatobiliary diseases of various causes, bilirubin uptake, storage, and excretion are impaired to varying degrees. Thus, both conjugated and unconjugated bilirubin is retained and a wide range of abnormal serum concentrations of each form of bilirubin may be observed. Both conjugated and unconjugated bilirubin are increased in hepatocellular diseases such as hepatitis and space-occupying lesions of the liver, and obstructive lesions such as carcinoma of the head of the pancreas, common bile duct, or ampulla of Vater.
Interpretation
Direct bilirubin levels must be assessed in conjunction with total and indirect levels and the clinical setting.
Clinical Reference
1. Tietz Textbook of Clinical Chemistry. Edited by CA Burtis, ER Ashwood. Philadelphia, PA, WB Saunders Company, 1994
2. Roche/Hitachi Modular Analytics Reference Guide, Vol 7
Report Available
Same day/1 to 2 daysMethod Name
Photometric, Diazotized Sulfanilic Acid
mml-liver-pancreatic