Pediatric vitamin D: Pseudo‐hypervitaminosis

BACKGROUND: Vitamin D toxicity is rare in pediatric population. Falsely elevated levels of 25‐hydroxyvitamin D have been reported as a major challenge with immunoassay methods for quantifying vitamin D metabolites. CASE PRESENTATION AND METHOD: Here, we present two pediatric cases of falsely elevated 25‐hydroxyvitamin D that resulted in unnecessary further testing. We also report significant same‐day variation in the measurement of 25‐hydroxyvitamin D using the Abbott i2000SR immunoassay. Samples were spun twice and their values were confirmed with the gold standard liquid chromatography‐tandem mass spectrometry (LC–MS/MS) method for confirmation. CONCLUSION: The addition of a centrifugation step prior to sample testing resolved the variation observed in the measurement of 25‐hydroxyvitamin D levels. The patient samples were confirmed with instruments from a different vendor and LC–MS/MS. Re‐centrifugation of samples resolved the variation in the 25‐hydroxyvitamin D values.