Pediatric vitamin D: Pseudo-hypervitaminosis

BackgroundVitamin 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 MethodHere, 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. ConclusionThe 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.

Automated summary

Two pediatric cases had falsely elevated 25-hydroxyvitamin D levels, leading to unnecessary further testing. The addition of a centrifugation step resolved the variation in the measurement of 25-hydroxyvitamin D levels. Confirmation with instruments from a different vendor and LC-MS/MS was performed.