title: European concerted action on anticoagulation. Minimum numbers of lyophilized plasma samples for ISI calibration of CoaguChek and TAS point-of-care whole blood prothrombin time monitors.
abstract: International sensitivity index (ISI) calibration of whole blood prothrombin time (PT) monitors is too complex. We previously simplified the method by using European Concerted Action on Anticoagulation (ECAA) lyophilized plasma samples with the TAS PT-NC (Bayer AG, Leverkusen, Germany) and the CoaguChek Mini (Roche Diagnostics, Mannheim, Germany) whole blood PT monitoring systems. The TAS PT-NC required a correction derived from the line of equivalence. Monte Carlo bootstrap analysis of reducing numbers of test samples was performed with both systems. Plasma samples from patients receiving coumarin (coumarin samples), healthy subjects (normal samples), and plasma samples artificially depleted of coagulation factors were used. With the TAS PT-NC, 20 coumarin samples or 20 artificially depleted samples with 7 normal samples gave reliable ISI and international normalized ratio and satisfactory precision. With the CoaguChek Mini, 30 coumarin and 10 normal samples were required. Simplification of ISI calibration of the 2 monitoring systems is possible using fewer ECAA lyophilized plasma samples than the 80 required according to the World Health Organization guidelines for conventional PT systems and previously recommended for fresh plasma samples tested on the same 2 monitoring systems.
authors.affiliation: ECAA Central Facility, School of Biological Sciences, University of Manchester, Manchester, England.
authors.forename: Leon
authors.initials: L
authors.lastname: Poller
authors.forename: Michelle
authors.initials: M
authors.lastname: Keown
authors.forename: Nikhil
authors.initials: N
authors.lastname: Chauhan
authors.forename: Anton M H P
authors.initials: AM
authors.lastname: van den Besselaar
authors.forename: Armando
authors.initials: A
authors.lastname: Tripodi
authors.forename: Jorgen
authors.initials: J
authors.lastname: Jespersen
authors.forename: Caroline
authors.initials: C
authors.lastname: Shiach
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000627:therapeutic use*; D002138:Calibration; D016903:Drug Monitoring / Q000295:instrumentation / Q000379:methods / Q000592:standards; D005060:Europe; D005612:Freeze Drying; D006801:Humans; D007391:International Cooperation; D019934:International Normalized Ratio / Q000295:instrumentation / Q000379:methods; D010949:Plasma; D019095:Point-of-Care Systems / Q000592:standards*; D011517:Prothrombin Time; D011817:Rabbits; D011934:Reagent Strips; D012015:Reference Standards; D018401:Sample Size; D013925:Thromboplastin / Q000592:standards
chemical_list: D000925:Anticoagulants; D011934:Reagent Strips; D013925:Thromboplastin