Self-monitoring of warfarin

Self-testing and self-managing are the 2 methods that constitute self-monitoring. Self-testing is when the patient or carer performs the INR test themselves using a point-of-care device, then contacts the general practitioner who determines the warfarin dose. Self-managing is when the patient or carer adjusts the warfarin dose by following the individualised protocol provided by the treating clinician.

Consider self-monitoring for patients on long-term warfarin therapy with a stable INR if the patient or carer prefers this form of testing and is both physically and cognitively able to self-monitor effectively.

Educate the patient or carer about all aspects of oral anticoagulant therapy (see Patient education about anticoagulant therapy). The patient or carer must:

• understand the responsibility of self-monitoring
• know when to contact the clinician for advice
• be trained in the correct use of the point-of-care monitor
• keep accurate records and share the information appropriately.

The clinician should regularly review the patient’s ability to self-monitor.

Use reliable quality control procedures (eg comparing the patient’s equipment with the general practice or clinic coagulometer) to check point-of-care equipment. The precision and accuracy of point-of-care coagulometers are generally acceptable compared with laboratory-based INR testingChristensen, 2012.

Self-monitoring increases a patient’s time in the therapeutic range, reduces clinic visits and, in some studies, reduces thromboembolic events without an increase in bleeding frequency or mortality compared with standard careNational Institute for Health and Care Excellence (NICE), 2014.