A method to correct for the influence of bovine serum albumin-associated vitamin D metabolites in protein extracts from neonatal dried blood spots

OBJECTIVE: We developed an assay to measure the concentration of 25 hydroxyvitamin D(2) and D(3) in protein extracts derived from stored neonatal dried blood spots. During this study, we postulated that these samples had been contaminated with exogenous vitamin D metabolites because of the addition of bovine serum albumin (BSA) as part of an extraction step undertaken 7 years earlier. The aim of the current study was to develop methods in order to adjust for this contamination. RESULTS: We identified between-plate variations in 25 hydroxyvitamin D(2) and D(3) concentrations which suggested the presence of three different BSA batches. Based on repeat extraction (without the addition of BSA) and testing of 395 samples, we developed models to correct for the exogenous 25 hydroxyvitamin D(2) and D(3.) The regression models were Diff(25OHD3) = − 8.2 + 1.8* Diff(25OHD2) for low contamination, Diff(25OHD3) = 23.8 + 1.7* Diff(25OHD2) for middle contamination, and Diff(25OHD3) = 14.3 + 3.0* Diff(25OHD2) for high contamination. After these corrections, the three subsamples had comparable distributions within the expected range for both 25 hydroxyvitamin D(2) and D(3). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13104-022-06077-1.