The stability of markers in dried-blood spots for recommended newborn screening disorders in the United States

Abstract

Objective: We aimed to measure separately the contributions of heat and humidity to changes in levels of 34 markers of inborn disorders in dried-blood-spot (DBS) samples. Design and methods: We stored paired sets of DBSs at 37. °C for predetermined intervals in low-humidity and high-humidity environments. Marker levels of all samples in each complete sample set were measured in a single analytic run. Results: During the 30 ± 5. day studies, galactose-1-phosphate uridyltransferase and biotinidase lost almost 65% of initial activities in low-humidity storage; most of the degradation in 27 other markers was attributable to adverse effects of high-humidity storage; seven markers in DBSs stored at high humidity lost more than 90% of initial levels by the end of the study and 4 of the 7 lost more than 50% of initial levels within the first week of storage. Conclusions: Minimizing both humidity and temperature in DBS transportation and storage environments is essential to maintaining sample integrity. © 2011 The Canadian Society of Clinical Chemists.