T Tuuminen — Page 2 | PubMed Health

PubMed1990

[Methods of determining phenylalanine in blood and blood stains dried on paper].

Two modifications of the method developed by McCaman and Robins are suggested for the screening of newborns for phenylketonuria and for monitoring the treatment of the detected patients. Phenylalanine levels are measured in the plasma and blood stains dried on the paper for express tests, brand 2, with the use of high-capacity (96 analyses per minute) Fluoroscan-2 fluorometer (Labsystems OY, Finland). A high analytical reliability of the methods is demonstrated. Use of microplates permits taking the minimal volumes of the tested material and reagents.

Blood Stains↗

PubMed1989

Fluorometric method for phenylalanine microplate assay adapted for phenylketonuria screening.

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.

Autoanalysis↗