[Comparison of the phenylalanine determination by ion exchange column chromatography and the guthrietest in treated phenylketonuric children (author's transl)].

Simultaneous measurements of phenylalanine by ion exchange column chromatography and microbiologal inhibition test according to Guthrie were performed on 22 treated children with phenylketonuria within two years. The results coincide in 40,3% (229 of 569 estimations), in 15,8% the real phenylalanine concentration by the method of Guthrie were overestimated, in 43,9% underestimated. Bacterial inhibition assay is successful in routine screening of phenylketonuria in the newborn, but not suitable for dietary control of phenylketonuria.