Falsely high serum creatinine concentration associated with severe methanol intoxication.

A case of severe methanol intoxication (1300 mg/L) was associated with markedly increased serum creatinine (490 mg/L) despite normal urea values and the absence of any other signs of renal disease. These values declined progressively to normal, and the patient recovered with no visual impairment. Additional laboratory experimentation suggested that the high creatinine value was probably ascribable to some unknown foreign material(s) in the patient's blood that reacted with the alkaline picrate used in the measurement of creatinine. One of the presumed metabolites of methanol, formaldehyde, reacts with creatinine but the product does not react with picrate. We believe that the foreign material was derived from either commercial preparations of methanol or contaminants in the patient's drinking water.