title: Evaluation of the Steelex M600H coagulometer prothrombin time-international normalized ratio assay with Steelex test reagents.
abstract: BACKGROUND
  The aim of the present study was to validate prothrombin time (PT) international normalized ratio (INR) results obtained using Steelex test reagents and a Steelex coagulometer (Steelex Scientific Instrument Company, Beijing, China), in comparison with use of a well-established standard test employing Pacific Hemostasis reagents (Fisher Diagnostics, Middletown, VA, USA) and Teco Coatron A4 coagulometer (Teco Medical Instruments GmbH, Neufahrn, Germany).
  
  
  METHODS
  Between- and within-day coefficients of variation (CVs) of both assays were calculated using control samples provided by the test manufacturers. Samples from 90 subjects were collected and INR values were determined in a double-blind parallel manner employing both systems.
  
  
  RESULTS
  The within-day coefficients of variation (CVs) in INR estimates ranged from 2.6% (INR = 1.12) to 3.1% (INR = 2.51) for the Steelex system and from 2.1% (INR = 1.09) to 1.8% (INR = 2.8) for the Pacific test; the between-day values ran from 3.4% (INR = 1.16) to 7.9% (INR = 2.64) and from 3.3% (INR = 1.1) to 2.3% (INR = 2.7), respectively. Passing-Bablok fit of the of the Steelex and Pacific methods yielded the equation: Steelex INR = 0.85 (0.79-0.91) x Pacific INR + 0.12 (-0.02-0.21), whereas the CUSUM linearity P value was < 0.01. The mean bias as determined by the Bland-Altman test was -0.156 (-0.912-0.600).
  
  
  CONCLUSIONS
  The results obtained using Steelex reagents and the M600H coagulometer are not equivalent to those obtained using Pacific Hemostasis reagents and a Teco Coatron A4 coagulometer, at least in the therapeutic range.
authors.affiliation: Department of Clinical Laboratory, Sevket Yilmaz Education and Training Hospital, Bursa, Turkey. yaseminbudak2000@yahoo.com
authors.forename: Yasemin U
authors.initials: YU
authors.lastname: Budak
authors.forename: Kağan
authors.initials: K
authors.lastname: Huysal
authors.forename: Murat
authors.initials: M
authors.lastname: Polat
authors.forename: Gülsevil
authors.initials: G
authors.lastname: Tarakçi
authors.forename: Hakan
authors.initials: H
authors.lastname: Uçar
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage; D001281:Atrial Fibrillation / Q000097:blood* / Q000188:drug therapy; D004311:Double-Blind Method; D006801:Humans; D019934:International Normalized Ratio; D011517:Prothrombin Time; D011933:Reagent Kits, Diagnostic
chemical_list: D000925:Anticoagulants; D011933:Reagent Kits, Diagnostic