A rapid method for estimating glucose concentrations in serum and in fluoride-, iodoacetate-, heparin-, and EDTA-treated plasma and whole blood is described. The procedure requires about three minutes to perform and utilize a tungstic acid precipitant solution and urine glucose dipsticks. Test results correlate with those of a reference quantitative glucose method at levels from 25 to 500 mg/dl (1.38 to 27.5 mmol/l). Hemolysis, lipemia and bilirubin levels as high as 20 mg/dl (342 mmol/l) do not interfere with the procedure. The simplicity and adaptability of the method make it useful in emergency situations.