Intoxication with nitromethane-containing fuels: Don't be 'fueled' by the creatinine

Background: This report describes two patients exposed to nitromethane-containing fuels and the resulting laboratory abnormalities. Patient 1 ingested model airplane fuel on two separate occasions; the second patient had dermal exposure from clothing saturated with fuel in a drag racing accident. After the exposure, both patients had unusually elevated serum creatinine concentrations. Methods: We determined the cause of the increase in serum creatinine to be due to nitromethane interfering with the Jaffe reaction used to measure this analyte. The interference was determined by both adding increasing quantities of nitromethane to sera and remeasuring the apparent creatinine and by retesting some of the original samples using an enzyme-based creatinine method. Results: We found nitromethane, in the concentrations absorbed or ingested by the patients, increased the apparent creatinine 10- to 20-fold. Conclusions: Nitromethane interferes with the most widely used colorimetric method used to measure creatinine. Management of this mixed poisoning should focus on the appropriate treatment for methanol toxicity, Extreme, but false, elevations of creatinine do not require hemodialysis when no other significant laboratory abnormality exists.