Objectives: Newborn screening for X-linked adrenoleukodystrophy utilizes tandem mass spectrometry to analyze dried-blood spot specimens. Quality control materials (dried-blood spots enriched with hexacosanoyl lysophosphatidylcholine) were prepared and stored at different temperatures for up to 518days to evaluate the stability of this biomarker for X-linked adrenoleukodystrophy.
Design and methods: Dried-blood spot storage included desiccant (45, 171, and 518days) or omitted desiccant (53days at >90% relative humidity). Specimens were stored for 171 and 518days at -20°C, 4°C, ambient temperature, and 37°C. Each weekday for 45days, a bag of specimens stored at 4°C was warmed to ambient temperature and one specimen was removed for storage at -80°C. Specimens were analyzed by high-performance liquid-chromatography electrospray ionization tandem mass spectrometry and data was plotted as concentration (micromoles per liter) vs. time. Linear regression provided slope and y-intercept values for each storage condition.
Results: Small slope values (0.01 or less) and y-intercept values close to the enrichment indicated less than 11% loss of hexacosanoyl lysophosphatidylcholine under all storage conditions tested.
Conclusions: Quality control materials for X-linked adrenoleukodystrophy are stable for at least 1year when stored with desiccant.
Keywords: Dried-blood spot; Lysophosphatidylcholine; Newborn screening; Tandem mass spectrometry; X-linked adrenoleukodystrophy.
Published by Elsevier Inc.