Overview: Total Bilirubin TestIntroduction: The Total Bilirubin Test measures total bilirubin levels to assess liver or blood disorders, causing jaundice or fatigue. Aligned with 2023 AASLD guidelines, it uses spectrophotometry for high sensitivity, aiding in liver screening. This test is critical for guiding diagnosis, treatment, and improving outcomes in biochemistry for patients with suspected liver or hemolytic disorders.
Other Names: Bilirubin Total Assay, Liver Function Test.
FDA Status: Laboratory-developed test (LDT), meeting biochemistry standards for diagnostic accuracy.
Historical Milestone: Bilirubin testing began in the 1910s with chemical assays. Spectrophotometry emerged in the 1960s, and by the 2000s, automated analyzers improved accuracy for liver and blood disorder detection.
Purpose: Diagnoses liver or hemolytic disorders, guides treatment, and monitors bilirubin levels in patients with jaundice or fatigue.
Test Parameters: 1. Bilirubin Total
Pretest Condition: Fasting for 10-12 hours required to stabilize bilirubin levels. Collect serum or plasma after overnight fasting. Report symptoms like jaundice or fatigue, and list medications like ursodeoxycholic acid or phenobarbital.
Specimen: 2-5 mL serum (SST) or 2-4 mL plasma (EDTA). Centrifuge within 1 hour. Transport in a biohazard bag within 8 hours.
Sample Stability at Room Temperature: 8 hours
Sample Stability at Refrigeration: 7 days
Sample Stability at Frozen: 6 months
Medical History: Document liver symptoms, hemolytic anemia, or family history of liver/blood disorders. Include current medications, especially those affecting liver function or red blood cell turnover.
Consent: Written consent required, detailing the tests purpose, diagnostic implications, and potential need for liver treatment or further testing.
Procedural Considerations: Uses spectrophotometry to measure total bilirubin levels. Results are available in 1-2 days, enabling rapid clinical decisions. Performed in laboratories with strict quality controls.
Factors Affecting Result Accuracy: Non-fasting samples, hemolysis, or medications like phenobarbital may alter results. Improper storage can degrade samples.
Clinical Significance: Elevated total bilirubin levels indicate liver dysfunction or hemolysis, prompting treatment or imaging. Normal levels suggest stable liver or blood function.
Specialist Consultation: Consult a hepatologist for result interpretation. A hematologist referral is advised for hemolytic cases.
Additional Supporting Tests: Direct bilirubin test, liver function tests, or CBC to confirm liver or blood disorders.
Test Limitations: False positives may occur with hemolysis or cholestasis. Results require clinical correlation with imaging or other markers.
References: AASLD Liver Guidelines, 2023; Hepatology, Lindor KD, 2022.
