title: Minimum numbers of fresh whole blood and plasma samples from patients and healthy subjects for ISI calibration of CoaguChek and RapidPointCoag monitors.
abstract: The international sensitivity index (ISI) calibration of point-of-care-test (POCT) prothrombin time (PT) whole blood monitors is complex, requiring manual PT testing of 60 patients' and 20 healthy subjects' plasma samples. The possibility of reducing these numbers was studied by a Monte Carlo Bootstrap study for 2 POCT PT systems. For reduced sample numbers, this consisted of 50,000 calibrations using whole blood and plasma samples tested on the monitors with manual PT testing of plasma samples from the same blood donations. There was little effect on mean ISI by reduction of sample numbers to a total of 7, but there was progressively less certainty regarding the reliability of the calibration. Precision of the calibrations and international normalized ratio deviation were not affected markedly by reducing numbers to half As ISI calibration with the 2 POCT systems was less precise than conventional manual testing, for maximum confidence, reduction of numbers is not advised.
authors.affiliation: European Concerted Action on Anticoagulation, Central Facility, School of Biological Sciences, University of 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; D001777:Blood Coagulation / Q000502:physiology*; D002138:Calibration; D006801:Humans; D019934:International Normalized Ratio; D009010:Monte Carlo Method; D010949:Plasma; D019095:Point-of-Care Systems; D011517:Prothrombin Time; D011817:Rabbits; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D018401:Sample Size; D012680:Sensitivity and Specificity; D013925:Thromboplastin / Q000592:standards*
chemical_list: D011933:Reagent Kits, Diagnostic; D013925:Thromboplastin