Langenbeck U, Behbehani A, Luthe H
J Inherit Metab Dis. 1981;4(2):69-70. doi: 10.1007/BF02263595.
Renal clearance of phenylpyruvic acid is maximal at a plasma concentration of 40-60 mumol/l. This concentration is obtained with plasma phenylalanine concentrations of 1.0-1.2 mmol/l, the threshold for separating classical phenylketonuria from phenylketonuria variants.