Methods for detecting dihydroxyvitamin d metabolites by mass spectrometry
AssigneeQuest Diagnostics Investments Incorporated
InventorsBrett HOLMQUIST, Nigel J. CLARKE, Anne Caston-Balderrama, Richard E. Reitz
Life of this patent
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Abstract
Provided are methods of detecting the presence or amount of a dihydroxyvitamin D metabolite in a sample using mass spectrometry. The methods generally comprise ionizing a dihydorxyvitamin 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. In certain preferred embodiments the methods include immunopurifying the dihydroxyvitamin D metabolites prior to mass spectrometry. Also provided are methods to detect the presence or amount of two or more dihydroxyvitamin D metabolites in a single assay.
Claims38
A method for determining an amount of one or more dihydroxyvitamin D metabolites in a biological sample by tandem mass spectrometry;
- the method comprising:
- (i) adding one or more internal standards to the sample;
- (ii) purifying the one or more dihydroxyvitamin D metabolites and the one or more internal standards;
- (iii) derivatizing the one or more dihydroxyvitamin D metabolites and the one or more internal standards with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD);
- (iv) analyzing the amount of the derivatized one or more dihydroxyvitamin D metabolites and the derivatized one or more internal standards in the sample by tandem mass spectrometry.
A method for determining an amount of 1α,25(OH)2D2 and 1α,25(OH)2D3 in a biological sample by tandem mass spectrometry, the method comprising:
- (i) adding d6-1α,25(OH)2D2 and d3-1α,25(OH)2D3 to the sample;
- (ii) extracting the 1α,25(OH)2D2, 1α,25(OH)2D3, d6-1α,25(OH)2D2, and d3-1α,25(OH)2D3 from the sample;
- (iii) purifying the 1α,25(OH)2D2, 1α,25(OH)2D3, d6-1α,25(OH)2D2, and d3-1α,25(OH)2D3;
- (iv) derivatizing the 1α,25(OH)2D2, 1α,25(OH)2D3, d6-1α,25(OH)2D2, and d3-1α,25(OH)2D3 with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD);
- (v) analyzing the amount of the derivatized 1α,25(OH)2D2, 1α,25(OH)2D3, d6-1α,25(OH)2D2, and d3-1α,25(OH)2D3 by tandem mass spectrometry;
- and
- (vi) determining the amount of 1α,25(OH)2D2 and 1α,25(OH)2D3 in the biological sample from step (v).
Dependencies are inferred from the claim text.