Routine methods in toxicology and therapeutic drug monitoring by high-performance liquid chromatography. I. Rapid method for determination of acetaminophen in plasma, including a STAT procedure.

A method has been developed for rapid determination of acetaminophen levels in plasma using high-performance liquid chromatography (HPLC) including a STAT procedure. Most often, determination of acetaminophen levels is requested in emergency situations. In such situations, hepatic toxicity can occur, in severe cases leading to hepatic failure. Hepatic toxicity is correlated with serum drug concentrations and, in particular, with biological half-life (t1/2). Because hepatic injury only becomes biochemically apparent 24-48 h after overdose ingestion, the potential for developing severe hepatic damage can be much more quickly assessed by determining the serum levels of acetaminophen. Certain concentrations in serum at 4 and 12 h after overdose are associated with probable hepatic damage. Therefore, one must know the levels as soon as possible; thus, STAT is most often ordered. The method described in this article was developed for running acetaminophen stats and is a microscale method, requiring only 10 microliter of the specimen; thus, it is also suitable for pediatric patients. The procedure involves precipitation of proteins and injection of the top clear liquid into the chromatogram.