title: Point-of-care (POC) versus central laboratory instrumentation for monitoring oral anticoagulation.
abstract: Point-of-care (POC) instruments employing fingerstick whole blood to monitor patients treated with warfarin are a popular alternative to complex, central laboratory coagulation analyzers utilizing citrated plasma derived from venipuncture. We investigated the accuracy of two widely utilized POC instruments for oral anticoagulation monitoring compared with a central laboratory instrument. Instrument-to-instrument variation differed for the two POC instruments, which correlated with the central laboratory instrument, but exhibited positive bias of 0.24 - 0.35 INR units. Positive bias increased as the INR values increased. We conclude that clinicians should exercise caution when interpreting results generated by POC monitors, particularly at high INR values. A high POC measurement of INR does not necessarily warrant decreasing the warfarin dose. Instead, a predefined cut-off range for high INR values generated by POC instruments should mandate confirmatory testing with central laboratory instrumentation.
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115,USA. ddorfman@partners.org
authors.forename: David M
authors.initials: DM
authors.lastname: Dorfman
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Goonan
authors.forename: M Kay
authors.initials: MK
authors.lastname: Boutilier
authors.forename: Petr
authors.initials: P
authors.lastname: Jarolim
authors.forename: Milenko
authors.initials: M
authors.lastname: Tanasijevica
authors.forename: Samuel Z
authors.initials: SZ
authors.lastname: Goldhaber
mesh_terms: D000925:Anticoagulants / Q000097:blood*; D006801:Humans; D019934:International Normalized Ratio / Q000379:methods*; D019095:Point-of-Care Systems; D011786:Quality Control; D015203:Reproducibility of Results; D014859:Warfarin / Q000097:blood*
chemical_list: D000925:Anticoagulants; D014859:Warfarin