What is the normal total bilirubin level in mg/dL?

What is the normal total bilirubin level in mg/dL?

• A. Less than 1 mg/dL
• B. 0.5-1.5 mg/dL
• C. Less than 0.5 mg/dL
• D. 1-2 mg/dL

Answer: (A)

Total bilirubin represents the sum of indirect (unconjugated) and direct (conjugated) bilirubin. In healthy adults, the liver processes bilirubin efficiently, so the total level stays at or below about 1 mg/dL (many references use up to ~1.2 mg/dL, but the common exam standard is <1 mg/dL). That makes "less than 1 mg/dL" the typical normal value. If total bilirubin rises, it points to possible bilirubin processing or excretion issues, such as increased bilirubin production from hemolysis (more indirect bilirubin) or impaired conjugation or biliary obstruction (more direct bilirubin, or a mixed rise). Newborns can have higher bilirubin temporarily, but in adults the usual cutoff remains around 1 mg/dL. The other ranges either extend into abnormal territory or are not representative of the common adult normal.

Total bilirubin represents the sum of indirect (unconjugated) and direct (conjugated) bilirubin. In healthy adults, the liver processes bilirubin efficiently, so the total level stays at or below about 1 mg/dL (many references use up to ~1.2 mg/dL, but the common exam standard is <1 mg/dL). That makes "less than 1 mg/dL" the typical normal value.

If total bilirubin rises, it points to possible bilirubin processing or excretion issues, such as increased bilirubin production from hemolysis (more indirect bilirubin) or impaired conjugation or biliary obstruction (more direct bilirubin, or a mixed rise). Newborns can have higher bilirubin temporarily, but in adults the usual cutoff remains around 1 mg/dL. The other ranges either extend into abnormal territory or are not representative of the common adult normal.