{"doi":"10.1093/clinchem/hvab013","title":"Chemical Characterization and Quantification of Circulating Intact PTH and PTH Fragments by High-Resolution Mass Spectrometry in Chronic Renal Failure","abstract":"BACKGROUND: The precise concentrations of full-length parathyroid hormone (PTH1-84) and the identity and concentrations of PTH fragments in patients with various stages of chronic renal failure are unknown. METHODS: We developed a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method to characterize and quantify PTH1-84 and PTH fragments in serum of 221 patients with progressive renal dysfunction. Following capture by matrix-bound amino-terminal or carboxyl-terminal region-specific antibodies and elution from matrix, PTH1-84 and PTH fragments were identified and quantitated using LC-HRMS. PTH was simultaneously measured using an intact PTH (iPTH) immunoassay. RESULTS: Full-length PTH1-84 and 8 PTH fragments (PTH28-84, 34-77, 34-84, 37-77, 37-84, 38-77, 38-84, and 45-84) were unequivocally identified and were shown to increase significantly when an eGFR declined to ≤17-23 mL/min/1.73m2. Serum concentrations of PTH1-84 were similar when measured by LC-HRMS following capture by amino-terminal or carboxyl-terminal immunocapture methods. In patients with an eGFR of <30 mL/min/1.73 m2, serum PTH concentrations measured using LC-HRMS were significantly lower than PTH measured using an iPTH immunoassay. PTH7-84 and oxidized forms of PTH1-84 were below the limit of detection (30 and 50 pg/mL, respectively). CONCLUSIONS: LC-HRMS identifies circulating PTH1-84, carboxyl-terminal PTH fragments, and mid-region PTH fragments, in patients with progressive renal failure. Serum PTH1-84 and its fragments markedly rise when an eGFR decreases to ≤17-23 mL/min/1.73 m2. PTH concentrations measured using LC-HRMS tend to be lower than those measured using an iPTH immunoassay, particularly in severe chronic renal failure. Our data do not support the existence of circulating PTH7-84 and oxidized PTH1-84.","journal":"Clinical Chemistry","year":2021,"id":168426,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":30,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9482,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":698570,"name":"Louis Losbanos","orcid":null,"position":1,"is_corresponding":false},{"id":265608,"name":"Jolaine M. Hines","orcid":null,"position":2,"is_corresponding":false},{"id":87341,"name":"Katherine O’Grady","orcid":"0000-0001-6043-1070","position":3,"is_corresponding":false},{"id":294953,"name":"Candice Z. Ulmer","orcid":"0000-0003-1477-6873","position":4,"is_corresponding":false},{"id":294957,"name":"Hubert W. Vesper","orcid":"0000-0002-9649-9015","position":5,"is_corresponding":false},{"id":339335,"name":"Felicity Enders","orcid":"0000-0002-3261-5400","position":6,"is_corresponding":false},{"id":397360,"name":"Ravinder J. Singh","orcid":"0000-0003-4538-6544","position":7,"is_corresponding":false},{"id":500996,"name":"Rajiv Kumar","orcid":"0000-0003-3497-3057","position":8,"is_corresponding":false},{"id":697768,"name":"Kittrawee Kritmetapak","orcid":"0000-0002-4506-5874","position":0,"is_corresponding":true}],"reference_count":43,"raw_metadata":null,"created_at":"2026-07-18T23:46:06.853307Z","pmid":"33693557","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}