A method for deriving normal ranges from laboratory specimens applied to uric acid in males.

Plasma specimens from male blood donors gave a normal range for uric acid concentration of 3.3 to 7.5 mg/100 ml. Specimens from male outpatients, which were received in the laboratory for the analysis of urea but not of uric acid and proved to have normal concentrations of urea, showed a positively skewed distribution of values for uric acid from which a ;normal range' of 3.2 to 7.6 mg/100 ml was derived. We suggest that specimens from outpatients selected in the way described here may prove to be a convenient source of data for determining the normal range of other substances.