Accuracy of a portable prothrombin time monitor (Coagucheck) in patients on chronic oral anticoagulant therapy: A prospective multicenter study

Benilde Cosmi, Gualtiero Palareti, Marco Moia, Monica Carpenedo, Vittorio Pengo, Alessandra Biasiolo, Patrizia Rampazzo, Giampietro Morstabilini, Sophie Testa

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A portable prothrombin time (PT) monitor allows patients on oral anticoagulant therapy (OAT) to measure their PT at home. The purpose of the study was to evaluate the accuracy and precision of a portable PT monitor (Coagucheck, Roche Diagnostics, Mannheim, Germany) as compared with laboratory methods. The prospective study was conducted in four centers of the Italian Federation of Anticoagulation Clinics. A one-month instruction phase was followed by a six-month surveillance phase. Seventy-eight subjects on stable OAT (48 men, 30 women, age range: 18-75) were selected on a volunteer basis. Dual measurements of INR values were performed in each subject both from finger capillary blood by the monitor and from venous blood by the Anticoagulation Clinic laboratory in three instruction sessions. The mean difference (bias) of the monitor INR results when compared with the average of laboratory INR and monitor INR results was -0.025 (limits of agreement-LA: -0.84/+0.81 INR units). The mean bias was -0.0675 (LA: -0.37/+0.23), +0.018 (LA: -0.39/+0.35), and +0.039 (LA: -0.49/+0.55), respectively, for INR values lower than 2.0, between 2.0 and 3.0, and greater than 3.0. The overall precision coefficient of monitor INR was 0.370, while it was 0.23, 0.46, 0.29, and 0.21, respectively, in Centers 1, 2, 3, and 4. The overall variation coefficient was 6.5% while it was 3.7%, 8.5%, 4.7%, and 4.9%, respectively, in Centers 1, 2, 3, and 4. Coagucheck has an acceptable level of accuracy for INR values in the range between 2.0 and 3.0. A wide variation in monitor performance was found among centers. Copyright (C) 2000 Elsevier Science Ltd.

Original languageEnglish
Pages (from-to)279-286
Number of pages8
JournalThrombosis Research
Issue number4
Publication statusPublished - Nov 15 2000



  • Accuracy
  • Anticoagulation clinic
  • Oral anticoagulants
  • Point-of-care testing
  • Precision
  • Prothrombin time

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Hematology

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