What is the reported potential use of acetaminophen-cysteine adduct (APAP-CYS) testing?
APAP-CYS testing could be used retrospectively to support or refute a diagnosis of acetaminophen-induced hepatotoxicity when ingestion source is unreliable or unavailable. APAP-CYS adducts are formed when NAPQI, the oxidative metabolite of acetaminophen binds to the cysteine residues of hepatic proteins. APAP-CYS adducts are released during hepatolysis and therefore elevated levels may be indicative of acetaminophen-induced liver injury and ultimately if an ingestion of acetaminophen occurred. (Curry SC, Padilla-Jones A, Ruha AM et al. The Relationship Between Circulating Acetaminophen-Protein Adduct Concentrations and Alanine Aminotransferase Activities in Patients With and Without Acetaminophen Overdose and Toxicity. J. Med. Toxicol. 2019 Jul; 15(3): 143-155.)