Falsely Elevated Acetaminophen Levels in the Setting of Hyperbilirubinemia

Patients presenting with elevated transaminases and jaundice are routinely tested for viral, autoimmune and drug etiologies. Acetaminophen (APAP) toxicity is a common and treatable cause of toxic hepatitis and elevated APAP levels in the setting of acute liver injury usually imply that acetaminophen is a primary contributor to the injury. Rare case reports, however, have described elevated levels in the absence of APAP ingestion in patients with hyperbilirubinemia and this appears to be related to the interference of bilirubin with commonly used assays for APAP.