Reference ranges
Bilirubin reference range
Reference ranges describe the interval a laboratory prints next to your result. They are not a diagnosis of what is “normal” for you personally — your clinician interprets results in context.
General biomarker education — not personalized medical advice. Learn more
What Bilirubin measures
Labs typically report total bilirubin, and sometimes direct and indirect fractions, reflecting how the liver is processing this byproduct.
Why ranges differ
Laboratories set their own reference intervals using their methods, equipment, and population data. That is why the range on your Quest report may differ from a LabCorp report — always use the interval printed on your source document.
Common units
Bilirubin is often reported in mg/dL. Confirm units on your original report before comparing values across time.