INR Monitoring

International Normalised Ratio (INR) testing will assist you to determine how your blood is clotting and is used to see if the anti-clotting medication you are using is working as it should, or whether changes are needed.

Blood-thinning medicines are usually prescribed for people who have atrial fibrillation (where the heart beats unevenly) or who have had artificial valves fitted.

These medicines do not actually make blood thinner. Rather, they work by increasing the time it takes for blood to clot and so their effectiveness is measured by how it increases the blood clotting time – and this is determined by an INR test.

Blood clotting helps your body stop bleeding. But blood clots can also cause strokes or heart attacks. The INR test helps balance the risk of internal bleeding against the risk of blood clotting.

The INR test is a simple blood test which can be taken at your community pharmacy and usually requires no preparation such as fasting or dietary changes.

However many medicines, foods and illnesses can affect this test so you should tell the pharmacist before the test about any medicines and supplements you are taking, as well as any changes in your diet.