Clinical Chemistry, Vol 17, 828-b-828, Copyright © 1971 by the American Association for Clinical Chemistry

Corrections

p 50: "Normal persons excrete less than 2 µmol of HPA per 24 h (3), less than 10 ng/200 to 30 µl" should read "Normal persons excrete less than 2 mg per day (3), i.e., less than 20 ng per 10 to 20 µl, assuming a daily urine volume 1 to 2 liters." Caption to Figure 1 should read: "We believe that it is essential to bracket all urine specimens with HPA standards, as is done in columns A, C, and E. 10 µl of raw urine from a patient with PKU is shown in column B. 10 µl of raw urine from a control child is shown in column D. Columns E, F, and G contain 0.50, 0.10 and 0.05 µl of a standard solution containing 1 mg HPA per ml of 95% ethanol, i.e., 500, 100, and 50 ng HPA, respectively."