Patent ID: 8383417

Claim:
A method for concurrently monitoring parathyroid hormone (PTH) variants in a biological sample, comprising steps of: preparing a sample containing PTH peptides from the biological sample, wherein the step of preparing the sample includes purifying and concentrating the PTH variants, proteolytically digesting a portion of the biological sample to produce PTH peptides, and chromatographically separating the sample; and subjecting the prepared sample to selective reaction monitoring (SRM) tandem mass spectrometry to concurrently determine the amounts of at least a first and a second PTH peptide, wherein the first PTH peptide is specific to a first PTH variant and the second peptide is specific to a second PTH variant; wherein the first PTH variant is intact PTH and the first PTH peptide is SEQ ID NO: 7 (SVSEIQLMHNLGK), and wherein the second PTH variant is a truncated form of PTH selected from a group consisting of PTH (34-84) and PTH (7-84).