The PREVENT trial showed strong evidence of the importance of long term low intensity oral anticoagulation therapy (OAT) in patients diagnosed with hyper-coagulable disorders following an initial venous thrombo-embolic event. The current study was designed to compare patient compliance, satisfaction, safety and time in range (TIR) with OAT monitored by either PST or standard laboratory methods. All patients enrolled had a history of at least one hyper-coagulable disorder and had experienced one or more thrombotic episodes prior to enrollment. Patients randomized to the PST arm were directed to test weekly using the ProTime Microcoagulation System (ITC, Edison, NJ); those in the control arm were directed to return to the clinic monthly for Prothrombin time/International Normalized Ratio (PT/INR) testing. Additional testing was encouraged for both groups in response to changes in diet, medication or clinical condition. Of the patients screened for the trial, eight patients randomized to the control arm completed the evaluation period and twenty-three patients randomized to the PST arm have completed at least 6 months of testing. Time in range was determined by the method described by Rosendaal where the INR results between two test dates are assumed to be evenly split between the two test results. The PST patients tested on average once every 9 days (range 5 – 16 days); demonstrating a mean TIR of 73% (range 45 – 90%). The control patients tested at an average frequency of once a month (range 0.3 – 3 months); demonstrating a mean TIR of 73% (range 24 – 96%). There were no statistical differences in the TIR or time above or below range between the two groups. Satisfaction surveys completed at the time of enrollment and after 3 and 6 months of PST showed strong endorsement of PST use. This pilot study demonstrates the utility of PST in the management of OAT in patients with a number of idiopathic coagulopathies and congenital hypercoagulable states (e.g., Protein C deficiency, hyperhomocysteinemia) as an alternative to routine clinical management without compromise to the patient's well-being.