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.

Abstract: The invention relates to the detection of vitamin D metabolites. In a particular aspect, the invention relates to methods for detecting derivatized vitamin D metabolites by mass spectrometry.

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 dihydroxyvitamin 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.

Abstract: Provided are methods for measuring renin activity in a plasma sample using mass spectrometry. The methods generally involve ionizing purified angiotensin 1 from the sample and detecting the amount of angiotensin 1 ions generated. The amount of detected angiotensin 1 ions are then related to the amount of angiotensin 1 generated in the sample, which in turn is related to renin activity in the sample.

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.

Abstract: Provided are methods for measuring renin activity in a plasma sample using mass spectrometry. The methods generally involve ionizing purified angiotensin 1 from the sample and detecting the amount of angiotensin 1 ions generated. The amount of detected angiotensin 1 ions are then related to the amount of angiotensin 1 generated in the sample, which in turn is related to renin activity in the sample.

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.

Abstract: Provided are methods for determining the amount of thyroglobulin in a sample using various purification steps followed by mass spectrometry. The methods generally involve purifying thyroglobulin in a test sample, digesting thyroglobulin to form peptide T129, purifying peptide T129, ionizing peptide T129, detecting the amount of peptide T129 ion generated, and relating the amount of peptide T129 ion to the amount of thyroglobulin originally present in the sample.

Abstract: The present invention relates to compositions and methods for analyzing analytes of interest in liquid samples by mass spectrometry, and preferably in patient samples. Preferred analytes of interest include sirolimus (rapamycin), corticosteroids, bile acids and lamotrigine (lamictal). In one embodiment, by careful selection of target ions, a number of corticosteroids can be analyzed simultaneously and without interference from closely related molecules. In another embodiment, the present methods combine high turbulence liquid chromatography with mass spectrometry performed in positive and negative mode in a single assay to enable the detection and quantification of the composition of bile acid pools. By combining mass spectrometry and high-throughput chromatography, the methods and compositions described herein can provide a rapid, sensitive, and accurate assay for use in large clinical laboratories.

Abstract: The invention relates to the detection of vitamin D metabolites. In a particular aspect, the invention relates to methods for detecting derivatized vitamin D metabolites by mass spectrometry.

Abstract: Provided are methods for determining the amount of thyroglobulin in a sample using various purification steps followed by mass spectrometry. The methods generally involve purifying thyroglobulin in a test sample, digesting thyroglobulin to form peptide T129, purifying peptide T129, ionizing peptide T129, detecting the amount of peptide T129 ion generated, and relating the amount of peptide T129 ion to the amount of thyroglobulin originally present in the sample.

Abstract: The invention relates to the detection of vitamin D metabolites. In a particular aspect, the invention relates to methods for detecting derivatized vitamin D metabolites by mass spectrometry.

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 dihydroxyvitamin 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.

Abstract: Provided are methods for determining the presence or amount of testosterone in a test sample, comprising ionizing all or a portion of the testosterone present in the sample to produce one or more testosterone ions that are detectable in a mass spectrometer. All or a portion of the testosterone present in the sample is ionized to produce one or more testosterone ions, which may be isolated and fragmented to produce precursor ions. A separately detectable internal testosterone standard can be provided in the sample. In a preferred embodiment, the reference is 2,2,4,6,6-d5 testosterone.

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.

Abstract: The invention relates to the detection of vitamin D metabolites. In a particular aspect, the invention relates to methods for detecting derivatized vitamin D metabolites by mass spectrometry.

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.

Abstract: Provided are methods of detecting the presence or amount of a dihydroxyvitamin in D metabolite in a sample using mass spectrometry. The methods generally comprise ionizing a dihydroxyvitamin 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.

Abstract: Provided are methods for determining the amount of underivatized dehydroepiandrosterone (DHEA) in a sample using mass spectrometry. The methods generally involve ionizing DHEA in a sample and detecting and quantifying the amount of the ion to determine the amount of DHEA in the sample.

Abstract: The invention relates to the detection of vitamin D metabolites. In a particular aspect, the invention relates to methods for detecting derivatized vitamin D metabolites by mass spectrometry.