Toxic exposure to acetaminophen is likely when an adult ingests >10 grams or 200 milligrams/kilogram in a single ingestion or over a 24-hour period, or >6 grams or 150 milligrams/kilogram/day for 2 consecutive days. Confirm toxicity with a serum acetaminophen concentration and determining the time of ingestion. Plot the serum acetaminophen level on the Rumack-Matthew nomogram (Fig. 106-1); this nomogram applies only to the setting of a single acute exposure and a window between 4 hours and 24 hours postingestion. Obtain additional laboratory studies, including electrolytes, glucose, BUN, creatinine, transaminases, CBC, and PT, ASA, urine toxicology screen, and ECG as clinically indicated (eg, potential coingestion in the suicidal patient).