If you take warfarin, your INR can be checked at any Bio-Test patient service centre in Ottawa and Eastern Ontario without an appointment: bring your Ontario health card and the standing requisition from your anticoagulation clinic or physician. The sample is processed at Bio-Test's own laboratory and the result is sent to the ordering provider promptly, with out-of-range values phoned through the same day.
What an INR test measures
INR stands for international normalised ratio. It expresses how long your blood takes to clot compared with a standard, so that results are comparable between laboratories. For most people not on blood thinners the INR is about 1.0. Warfarin is dosed to keep the INR in a target range, commonly 2.0 to 3.0, or 2.5 to 3.5 for some mechanical heart valves.
How often is INR checked?
When warfarin is started, INR is checked every few days until it is stable, then weekly, then every two to four weeks. Any change in dose, diet, alcohol, illness or another medication can move the INR, so your clinic may ask for an extra test. Many patients in Ottawa are followed by a hospital anticoagulation clinic or by their family physician; either can write a standing requisition that lets you walk in for repeat tests.
Do I need to fast or stop anything?
No fasting is needed. Take your warfarin at the usual time; most clinics prefer you take it in the evening so the morning INR reflects a steady level. Do not change the dose yourself based on a result; wait for the clinic's instruction.
Where to get an INR test in Ottawa
Any of Bio-Test's 11 centres can draw an INR. The Locations page shows live hours and the nearest site, from Bells Corners and Parkdale to Orléans, Carp, Embrun, Cornwall and Carleton Place. Walk-in, first come first served, typical wait under 15 minutes.
- Bring your health card and the requisition, or tell the desk which clinic holds your standing order.
- Mention if you have a dose change pending so the report is flagged for the clinic.
- If you are on a home INR meter, still do the lab check your clinic schedules to keep the meter calibrated.
How results reach your clinic
INR is run in-house and reported to the ordering provider, normally the same or next business day; results that are far out of range are phoned to the provider immediately. You can also see your result in the patient portal. Your clinic, not the laboratory, adjusts the dose and tells you the next test date.
Is an INR test covered by OHIP?
Yes. INR monitoring ordered by an authorized provider is insured with a valid Ontario health card. Read more about OHIP coverage of blood tests.