Simultaneous quantitative estimation of galactose-1-phosphate and galactose in blood for the diagnosis of galactosemia.

A new microfluorometrical simultaneous assay method of galactose-1-phosphate and galactose in blood discs was devised by use of alkaline phosphatase and beta-galactose dehydrogenase. Our method statistically corresponded well with the Kirkman's method. It can detect 1 X 10(-10) mole of minimal concentration of galactose-1-phosphate and galactose in one blood disc paper (3 mm in diameter), and this means the sensitivity of assay of galactose-1-phosphate was 0.1 mg%. Assay range in our method was very broad (0-2 mM or 0-10 mM). The accuracy and reproducibility of galactose-1-phosphate assay were 3.4 +/- 0.1 mg%, 8.0 +/- 0.4 mg% or 15.1 +/- 0.6 mg%. Mean values of galactose-1-phosphate and galactose in blood on normal infants were 0.8 mg% and 0.3 mg%, respectively. We applied this method to mass screening of galactosemia and could accurately distinguish many positive and false positive cases detected by Paigen's and Beutler's methods. This method gave us an easy and accurate assay system for the diagnosis of uridyl transferase and galactokinase deficiencies.