title: The variation in high sensitive cardiac troponin concentration during haemodialysis treatment is not similar to the biological variation observed in stable end stage renal disease patients.
abstract: BACKGROUND
  Cardiovascular mortality is high in end stage renal disease (ESRD). This study aimed to: (1) calculate within-week within- and between-subject biological variation (CVIand CVG) for hs-cTn in ESRD; (2) determine the magnitude of hs-cTn concentration changes during haemodialysis (HD) treatment; and (3) compare the CVIand CVGto the within and between-subject variation of cTn concentration changes during HD treatments (CVDIFF-Iand CVDIFF-G).
  
  
  METHODS
  Serum samples were collected from 20 patients before and after 10 consecutive HD treatments. cTn were measured using the hs-cTnT (Roche Diagnostics) and the hs-cTnI (Abbott Diagnostics). The CVA, CVI,CVG, CVDIFF-Iand CVDIFF-G, were estimated using nested ANOVA.
  
  
  RESULTS
  The within-week data showed hs-cTnT CVA, CVIand CVGof 1.6, 7.3 and 94.4%. Reference change values (RCV) were estimated to -18.7-23.0%. The Index of individuality (II) was 0.08. Corresponding values for hs-cTnI were 5.3, 13.2 and 142.4%, whilst the RCV was -32.5-48.2% and the II was 0.10. The mean concentration of cTn decreased by -6.4% (hs-cTnT) and -7.6% (hs-cTnI) during HD treatment. The CVDIFF-Iand CVDIFF-Gwas 4.2 and 6.3% for hs-cTnT, and 10.7 and 9.4% for hs-cTnI. The RCVDIFFwas -18.2-5.4% (hs-cTnT) and -39.0-23.8% (hs-cTnI), respectively, and the IIDIFF-values were 0.7 and 1.3.
  
  
  CONCLUSIONS
  The CVIand CVGare similar to earlier findings. Mean hs-cTn concentrations decreased during HD. The within-subject hs-cTn variation during HD is similar to the between-subject variation, i.e. determining a cut-off value for hs-cTn changes during HD may be useful.
authors.affiliation: a Laboratory of Clinical Biochemistry , Stavanger University Hospital , Stavanger , Norway.
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Skadberg
authors.affiliation: b Laboratory of Clinical Biochemistry , Haukeland University Hospital , Bergen , Norway.|c The Norwegian Quality Improvement of Primary Care Laboratories (NOKLUS), Department of Public Health and Primary Health Care , University of Bergen , Bergen , Norway.
authors.forename: Sverre
authors.initials: S
authors.lastname: Sandberg
authors.affiliation: c The Norwegian Quality Improvement of Primary Care Laboratories (NOKLUS), Department of Public Health and Primary Health Care , University of Bergen , Bergen , Norway.
authors.forename: Thomas
authors.initials: T
authors.lastname: Røraas
authors.affiliation: c The Norwegian Quality Improvement of Primary Care Laboratories (NOKLUS), Department of Public Health and Primary Health Care , University of Bergen , Bergen , Norway.
authors.forename: Per Hyltoft
authors.initials: PH
authors.lastname: Petersen
authors.affiliation: d Department of Gynaecology , Haukeland University Hospital , Bergen , Norway.
authors.forename: Hilde
authors.initials: H
authors.lastname: Sellevoll
authors.affiliation: e Department of Medicine , Haukeland University Hospital , Bergen , Norway.
authors.forename: Einar
authors.initials: E
authors.lastname: Svarstad
authors.affiliation: e Department of Medicine , Haukeland University Hospital , Bergen , Norway.
authors.forename: Kristin
authors.initials: K
authors.lastname: Sæle
authors.affiliation: b Laboratory of Clinical Biochemistry , Haukeland University Hospital , Bergen , Norway.
authors.forename: Kristin Moberg
authors.initials: KM
authors.lastname: Aakre
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000787:Angina Pectoris / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D012016:Reference Values; D006435:Renal Dialysis; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood*; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I; D020107:Troponin T
keywords: 99th percentile; Acute coronary syndrome; chronic kidney disease; diagnostic cut-off; interpretation of changes; myocardial infarction