What is the critical total bilirubin value listed?

• A. > 18 mg/dL
• B. < 1 mg/dL
• C. 5-10 mg/dL
• D. 15-20 mg/dL

Answer: (A)

Critical values in lab testing are levels that require immediate clinician notification because they signal potential life-threatening or rapidly worsening conditions. For total bilirubin, a threshold greater than 18 mg/dL is used as the critical point because such extreme hyperbilirubinemia can reflect severe liver dysfunction, biliary obstruction, or massive hemolysis and warrants urgent evaluation and management. Normal total bilirubin is roughly 0.3 to 1.2 mg/dL; jaundice typically appears at lower levels, but the urgent, actionable alert is set well above normal, at and beyond about 18 mg/dL. Values in the range of 5–10 mg/dL or 15–20 mg/dL indicate significant elevations, but the defined critical cutoff is the level exceeding 18 mg/dL, which triggers immediate clinical attention.