B-183 The Impact of 3-EPI-25-Hydroxyvitamin D on 25-Hydroxyvitamin D Measurement by Liquid Chromatography/Mass Spectrometry

Abstract Background 25-hydroxyvitamin D is the recommended target to evaluate vitamin status. The accurate measurement of by liquid chromatography/mass spectrometry (LC/MS/MS) impacted presence biologically inactive epimer D2 and D3, 3-EPI-25-hydroxyvitamin D3. epimers are isomers share same mass fragment transitions as For an should be chromatographically separated from D. Herein we assess significance in our patient population. Methods A LC/MS/MS method was developed separate D3 on a Waters Xevo TQ-S Micro with Acquity UPLC System using 2.6 μm Pentafluorophenyl (PFP) column (Phenomenex). There were 231 residual serum samples analyzed. Results cohort tested consisted 16 infant (<1 years), 62 pediatric (1–17 adult (≥18 20 pregnant samples. not detected any sample analyzed ng/mL). prevalence concentration variable (Fig. 1). Conclusion specificity affected it present However, significant interference. highest infants. decrease age minimal pregnancy. samples, assay that separates needed. may appropriate epimer. this population balance between accuracy throughput must established.