title: Prevalence of 25-hydroxyvitamin D₂ in Western New York: a 3-year study.
abstract: BACKGROUND
  We evaluated the distribution of 25OH-D2 and 25OH-D3 in a general patient population in Western New York to provide insights into how common detectable vitamin D2 is among samples from a general patient population.
  
  
  METHODS
  Serum 25OH-D2 and 25OH-D3 results measured by LC-MS/MS from June 2009 to December 2012 were retrospectively analyzed.
  
  
  RESULTS
  A total of 266,269 serum tests were included for analysis. The percentage of tests with 25OH-D2 levels above the assay limit of quantitation (LoQ) decreased from 32% to 17% over the course of the study period. The percentage of tests with 25OH-D2 levels higher than those of 25OH-D3 decreased from 21% to 12%. Sixty-seven percent of the test results with 25OH-D2 levels above the LoQ had serum concentrations of 25OH-D2 higher than those of 25OH-D3.
  
  
  CONCLUSIONS
  Prevalence of tests with quantifiable 25OH-D2 decreased over time and yet 17% of them still had detectable levels of 25OH-D2, 67% of which had 25OH-D2 levels higher than 25OH-D3. To achieve accurate 25-hydroxyvitamin D measurement, clinical laboratories should assess the accuracy of their assays, and if necessary, determine the local prevalence of 25OH-D2 to determine if mass spectrometry is the platform of choice to assess vitamin D deficiency.
authors: Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Strong Memorial Hospital, Rochester, NY, United States. Electronic address: Victoria_Zhang@URMC.Rochester.edu.
authors: Yan Victoria
authors: YV
authors: Zhang
authors: Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Strong Memorial Hospital, Rochester, NY, United States.
authors: Moritz
authors: M
authors: Stolla
authors: Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Strong Memorial Hospital, Rochester, NY, United States.
authors: Tai C
authors: TC
authors: Kwong
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D002112:Calcifediol / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D053719:Tandem Mass Spectrometry
chemical_list: D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol
keywords: 25-hydroxyvitamin D; Immunoassay; Mass spectrometry; Vitamin D; Vitamin D deficiency; Vitamin D(2); Vitamin D(3)