Apparent Elevated Creatinine After Ingestion of Nitromethane: Interference With the Jaffe reaction

We assessed a 2-year 4-month-old boy found to have a persistently elevated serum creatinine (peak 926 mu mol/L) as measured by the Jaffe reaction after ingesting an unknown quantity of fuel for a model car, which commonly contains nitromethane. The patient was otherwise clinically well and the remaining investigations were unremarkable. When creatinine concentrations were measured with specific enzymatic testing on these same blood samples, all values were within normal limits. Nitromethane has been shown to interfere with the determination of serum creatinine through the Jaffe reaction. Because many ingestions present only rarely, it is not possible for the emergency department clinician to be aware of all toxin factors affecting patient management. This case illustrates the importance of analysis of laboratory results in the context of the patient's clinical status.