Patent ID: 7901944
Filing Date: 2011-03-08
Classification: G01N,H01J,Y10T

Abstract:
1. A method for diagnosing a vitamin D deficiency or hypervitaminosis D in a mammalian patient, comprising: a) obtaining a biological sample from the mammalian patient; b) simultaneously determining an amount of 25-hydroxyvitamin D2 and an amount of 25-hydroxyvitamin D3 in a single sample derived from the mammalian patient's biological sample, wherein the determining comprises using a mass spectrometry technique to detect underivatized 25-hydroxyvitamin D2 and underivatized 25-hydroxyvitamin D3 in the single sample, wherein the mass spectrometry technique comprises a LC-MS/MS technique and wherein the LC-MS/MS technique comprises the use of a triple quadrupole instrument in Multiple Reaction Monitoring (MRM), positive-ion mode; c) comparing the amount of total 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 in the single sample with clinical reference values indicative of vitamin D deficiency or hypervitaminosis D; and d) diagnosing either a vitamin D deficiency or hypervitaminosis D, or neither, in the mammalian patient based on the comparisons in step c).