Serum Acetaminophen Protein Adduct Concentrations in Pediatric Emergency Department Patients

OBJECTIVES: Acetaminophen toxicity is a common cause of pediatric liver failure. The diagnosis may be limited by the short window of detection of acetaminophen in serum. Recently acetaminophen protein adducts (APAP-CYS) have been used as a biomarker with a longer duration of detection. The objective of this study was to describe the serum concentrations of APAP-CYS in pediatric patients with and without reported therapeutic acetaminophen exposure. METHODS: A cross-sectional study of children age 1 to <12 years presenting to a pediatric emergency department. Subjects were stratified by recent acetaminophen use and had serum APAP-CYS measured using LC/MS. RESULTS: One hundred patients were enrolled. All of the patients whose caregivers denied acetaminophen exposure had nondetectable APAP-CYS. Fifty-two percent of subjects who were reported to have taken acetaminophen in the preceding 2 weeks had detectable serum APAP-CYS. The APAP-CYS concentrations were positively correlated with higher overall dose and more recent ingestion. CONCLUSIONS: APAP-CYS is detectable in the majority of children taking acetaminophen and not detected in the majority of children who are not exposed to acetaminophen.