Methods for detecting vitamin D metabolites
AssigneeQuest Diagnostics Investments Incorporated
InventorsNigel Clarke, Brett Holmquist, Kwang-Ja Lee, Richard E. Reitz
Life of this patent
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Abstract
Provided are methods of detecting the presence or amount of a vitamin D metabolite in a sample using mass spectrometry. The methods generally comprise ionizing a vitamin D metabolite in a sample and detecting the amount of the ion to determine the presence or amount of the vitamin D metabolite in the sample. Also provided are methods to detect the presence or amount of two or more vitamin D metabolites in a single assay.
Claims23
A method for determining the presence or amount of 25-hydroxyvitamin D3 in a biological sample, comprising:
- (a) ionizing said 25-hydroxyvitamin D3, if present in said sample to produce a 25-hydroxyvitamin D3 ion;
- (b) isolating said 25-hydroxyvitamin D3 ion by mass spectrometry to provide a precursor ion having a mass/charge ratio (m/z) of about 383.2;
- (c) effecting a collision between the isolated precursor ion and an inert collision gas to produce at least one fragment ion detectable in a mass spectrometer;
- and
- (d) detecting the presence or amount of at least one of said precursor or fragment ions by mass spectrometry, wherein the presence or amount of said ion is related to the presence or amount of 25-hydroxyvitamin D3 in said test sample;
- wherein said sample is purified by chromatography prior to said ionization step.
A method for determining the presence or amount of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in a test sample in a single assay using tandem mass spectromety, said method comprising:
- (a) ionizing said 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2, if present in said sample, to generate ions specific for each of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2;
- and
- (b) detecting the presence or amount of at least one of said ions specific for each of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 by mass spectrometry, wherein the presence or amount of said ions is related to the presence or amount of said 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in said test sample;
- wherein at least one of said ions detected by mass spectrometry is an ion selected from the group consisting of ions having a mass/charge ration of about 211.35, 179.1, 209.20, and 251.30;
- wherein said sample is purified by chromatography prior to said ionization step.
A method for determining the presence or amount of 25-hydroxyvitamin D2 in a biological sample, comprising:
- (a) ionizing said 25-hydroxyvitamin D2, if present in said sample to produce a 25-hydroxyvitamin D2 ion;
- (b) isolating said 25-hydroxyvitamin D2 ion by mass spectrometry to provide a precursor ion having a mass/charge ratio (m/z) of about 395.3;
- (c) effecting a collision between the isolated precursor ion and an inert collision gas to produce at least one fragment ion detectable in a mass spectrometer;
- and
- (d) detecting the presence or amount of at least one of said precursor or fragment ions by mass spectrometry, wherein the presence or amount of said ion is related to the presence or amount of 25-hydroxyvitamin D2 in said test sample;
- wherein said sample is purified by chromatography prior to said ionization step.
Dependencies are inferred from the claim text.