Because VKAs may take up to several days before they reach efficacy, testing INR frequently is mandatory at the onset of treatment:
Of course, if testing more frequently means the patient must travel to a clinic or lab, this may put stress on their quality of life including time away from work, restriction on travel, costs for travel. For most patients, testing twice or four times per month is not a feasible option if travel to a lab, clinic or physician’s office is required. Yet many patients can be trained to test at home once per week or twice per month, providing a greater quality of life both medically and personally.
Together with you, the medical professional, properly trained patients and/or caregivers are capable of performing reliable PT testing and even adjusting their medication accordingly(3). For these patients, self-testing or self-managing is cost-effective and leads to outcomes at least as good as standard INR testing in a specialized clinic.(1, 2, 4-7)