Newborn screening of homocystinuria: quantitative analysis of total homocyst(e)ine on dried blood spot by liquid chromatography with fluorimetric detection

Abstract

Identification of homocystinuric newborns is hindered by the pitfalls of neonatal screening programs. We propose a fluorimetric HPLC method with a rapid pre-analytical step for homocysteine determination from neonatal dried blood spot cards. Homocysteine in blood spots sampled among 2000 healthy newborns on living day 4, averaged 2.92+/-2.07 microM (range 0.4-7.5). In eight homocystinuric control children, mean values were 61.71+/-52.84 microM (range 18.9-145.7). The method showed a good linearity (r=0.999), precision (RSD<7%) and recovery (95%). The correlation between blood spots and plasma samples was r=0.90. This method has all the essential features for a homocystinuria screening program: an easy and rapid pre-analytical step combined with method linearity and precision.