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: 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 vitamin C in a sample using mass spectrometry. The methods generally involve ionizing vitamin C in a sample and detecting and quantifying the amount of the ion to determine the amount of vitamin C 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 directed to 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 provides methods of preparation of lipoproteins from a biological sample, including HDL, LDL, Lp(a), IDL, and VLDL, for diagnostic purposes utilizing differential charged particle mobility analysis methods. Further provided are methods for analyzing the size distribution of lipoproteins by differential charged particle mobility, which lipoproteins are prepared by methods of the invention. Further provided are methods for assessing lipid-related health risk, cardiovascular condition, risk of cardiovascular disease, and responsiveness to a therapeutic intervention, which methods utilize lipoprotein size distributions determined by methods of the invention.

Abstract: The invention provides methods of preparation of lipoproteins from a biological sample, including HDL, LDL, Lp(a), IDL, and VLDL, for diagnostic purposes utilizing differential charged particle mobility analysis methods. Further provided are methods for analyzing the size distribution of lipoproteins by differential charged particle mobility, which lipoproteins are prepared by methods of the invention. Further provided are methods for assessing lipid-related health risk, cardiovascular condition, risk of cardiovascular disease, and responsiveness to a therapeutic intervention, which methods utilize lipoprotein size distributions determined by methods of the invention.

Abstract: Provided are methods of detecting the presence or amount of a vitamin D metabolite in a sample using mass spectrometry. The methods generally directed to 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: Methods are provided for determining the amount of an IGF-I and/or IGF-II protein in a sample using high resolution/high accuracy mass spectrometry. The methods generally comprise enriching an IGF-I and/or IGF-II protein in a sample, ionizing an IGF-I and/or IGF-II protein from the sample to generate IGF-I and/or IGF-II protein ions, and determining the amount of IGF-I and/or IGF-II protein ions with high resolution/high accuracy mass spectrometry.

Abstract: Provided are methods of detecting the presence or amount of the active form of vitamin B6, pyridoxal 5?-phosphate, in a body fluid sample using tandem mass spectrometry coupled with liquid chromatography.

Abstract: Provided are methods for determining the amount of total thiamine in a body fluid sample using liquid chromatography and mass spectrometry. Total thiamine is converted to free thiamine by treatment with an acid phosphatase prior to thiamine separation and quantification.

Abstract: Provided are methods for determining the amount of total thiamine in a body fluid sample using liquid chromatography and mass spectrometry. Total thiamine is converted to free thiamine by treatment with an acid phosphatase prior to thiamine separation and quantification.

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: Methods are described for measuring the amount of a kisspeptin-54-derived peptides in a sample. More specifically, mass spectrometric methods are described for detecting and quantifying a kisspeptin-54 derived peptides in a sample utilizing on-line extraction methods coupled with tandem mass spectrometric techniques.

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: Methods are provided for determining the amount of an IGF-I and/or IGF-II protein in a sample using high resolution/high accuracy mass spectrometry. The methods generally comprise enriching an IGF-I and/or IGF-II protein in a sample, ionizing an IGF-I and/or IGF-II protein from the sample to generate IGF-I and/or IGF-II protein ions, and determining the amount of IGF-I and/or IGF-II protein ions with high resolution/high accuracy mass spectrometry.

Abstract: Provided are methods for determining the amount of estrone in a sample using mass spectrometry. The methods generally involve ionizing estrone in a sample and detecting and quantifying the amount of the ion to determine the amount of estrone 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 composit˜on 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: 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: Methods are described for determining the amount of insulin in a sample. Provided herein are mass spectrometric methods for detecting and quantifying insulin and C-peptide in a biological sample utilizing enrichment and/or purification methods coupled with tandem mass spectrometric or high resolution/high accuracy mass spectrometric techniques. Also provided herein are mass spectrometric methods for detecting and quantifying insulin and b-chain in a biological sample utilizing enrichment and/or purification methods coupled with tandem mass spectrometric or high resolution/high accuracy mass spectrometric technique.