title: Fluorometric method for phenylalanine microplate assay adapted for phenylketonuria screening.
abstract: We adapted the method of McCaman and Robins for fluorometry of phenylalanine to a microplate assay for routine phenylketonuria screening. Sensitivity is 15 mumol/L for the plasma assay and 30 mumol/L for the dried blood-spot assay, with CV less than 10% for both assays. Results for human plasma by microplate assay correlated well (r = 0.99) with results of amino acid analyzer determination of phenylalanine. When measurements are performed in an automated reader, the microplate assay has considerable advantages over conventional measurements in cuvettes: smaller volumes of reagents and automation enabling high throughput and convenience. Because the described method is a quantitative one, we can postulate that, compared with the semiquantitative Guthrie inhibition bioassay, this microplate assay is more reliable, easier to perform, and about twofold less costly.
authors: All-Union Center for Phenylketonuria, Moscow, U.S.S.R.
authors: N S
authors: NS
authors: Gerasimova
authors: I V
authors: IV
authors: Steklova
authors: T
authors: T
authors: Tuuminen
mesh_terms: D001322:Autoanalysis; D006801:Humans; D008403:Mass Screening; D008832:Microchemistry / Q000191:economics / Q000379:methods; D010649:Phenylalanine / Q000032:analysis* / Q000097:blood / Q000652:urine; D010661:Phenylketonurias / Q000378:metabolism / Q000517:prevention & control*; D013050:Spectrometry, Fluorescence
chemical_list: D010649:Phenylalanine