We enrolled 82 patients receiving oral anticoagulation in a pilot trial of a point-of-care (POC) prothrombin time (PT) device in a patient self-testing (PST) application in 7 US and Canadian hospital-based anticoagulation centers. The properly selected and suitably trained patients were given the PT device to test at home for 6 weeks. Patients returned within 3 hours of the self-test to the hospital clinic where a repeated test was performed by a health care professional using the patient's POC device (clinic). Blood specimens were obtained for routine laboratory PT determinations by the local hospital laboratory (hospital) and a reference laboratory. International Normalized Ratio agreement between the home test and the clinic test was excellent. Home results correlated well with reference laboratory results. Using the reference laboratory as a standard, 68% of hospital and 66% of home results matched the patient's therapeutic range classification of the reference laboratory result. Participants overwhelmingly reported satisfaction and willingness to perform the self-test. Our results confirm the equivalence of the PST PT and a reference laboratory result and suggest that PST PT technology is an appropriate and useful adjunct to routine oral anticoagulation monitoring methods.