A New Method of Blood Galactose Estimation for Mass Screening of Galactosemia

Abstract

FUJIMURA, Y., KAWAMURA, M. and NARUSE, H. A New Method of Blood Galactose Estimation for Mass Screening of Galactosemia. Tohoku J. exp. Med., 1981, 133 (4), 371-378 -A new method for quantitative determination of galactose in blood by fluorescence of NADH was described. The assay system consisted of β-galactose dehydrogenase, NAD, buffer and a denatured blood disc (3mm diameter), and the reaction was carried out for 1 hr at 37°C. Denaturation of hemoglobin was accomplished by exposing the blood disc to a vapor of formic acid in an air-tight container; this procedure completely eliminated false positive cases of galactosemia. This method can be applied in a wide range of galactose concentration from low (0mg%) to high levels (200-1, 000mg%) with the accuracy of 8.0±0.3mg% from a coefficient of variation of 3.5%. Semi-quantitative assay was also possible by using a spot test like Beutler's method. The galactose content in one disc paper (3mm diameter) of blood containing 5mg% galactose is approximately 0.1μg. The newly developed method is satisfactorily applicable in neonatal mass screening and clinical cases.