title: The influence of sample site on intraoperative PTH monitoring during parathyroidectomy.
abstract: BACKGROUND
  Intraoperative parathyroid hormone (IOPTH) monitoring is common during parathyroidectomy. We hypothesized that sample site (peripheral vs central vein) may impact IOPTH interpretation.
  
  
  METHODS
  Two hundred and one patients underwent curative parathyroidectomy for single-gland disease. IOPTH was drawn peripherally (PV) in 114 patients and centrally (CV, jugular vein) in 87 patients. Decrease from baseline IOPTH and the presence of a normal value at 10 and 15 minutes were determined. The slope of IOPTH decay was calculated. These data were compared between sample sites.
  
  
  RESULTS
  Median baseline IOPTH was 268 pg/mL (CV) and 191 pg/mL (PV, P = .003). The mean IOPTH decay slopes were -0.75 (PV) and -0.76 (CV, P = NS), and the mean percent IOPTH decrease at 10 minutes was 79% PV and 80% CV (P = NS). At 10 minutes, a > or =50% drop from baseline was seen in 94% (CV) versus 97% (PV) of patients ( P = NS), resulting in a median IOPTH of 40 pg/mL (CV) versus 34 pg/mL (PV, P = .09). By 15 minutes, the central IOPTH had decreased by > or =50% of baseline in 98% of patients ( P = NS when compared to the 10-minute PV site).
  
  
  CONCLUSIONS
  IOPTH kinetics are largely the same for PV and CV sample sites, but baseline values are higher with central sampling. Consequently, CV IOPTH levels are generally higher at 10 minutes, but this discrepancy resolves by 15 minutes. The surgeon utilizing CV samples may need to extend the sampling period.
authors.affiliation: Department of Surgery, University of Michigan, Taubman Center TC2920H, 1500 East Medical Center Drive, Ann Arbor, MI 48109-0331, USA.
authors.forename: Derek T
authors.initials: DT
authors.lastname: Woodrum
authors.forename: Brian D
authors.initials: BD
authors.lastname: Saunders
authors.forename: Barry G
authors.initials: BG
authors.lastname: England
authors.forename: Richard E
authors.initials: RE
authors.lastname: Burney
authors.forename: Gerard M
authors.initials: GM
authors.lastname: Doherty
authors.forename: Paul G
authors.initials: PG
authors.lastname: Gauger
mesh_terms: D001800:Blood Specimen Collection; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood / Q000601:surgery*; D008297:Male; D016343:Monitoring, Intraoperative; D010280:Parathyroid Glands / Q000098:blood supply; D010281:Parathyroid Hormone / Q000097:blood*; D016105:Parathyroidectomy; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D010281:Parathyroid Hormone