How can you self-manage and adjust anticoagulants in the long term?

People who are on vitamin K antagonists usually have the clotting ability of their blood checked regularly. For this purpose, a blood sample is taken and the INR value (international normalized ratio) is measured. The INR value reflects the blood-clotting speed.

An INR around 1 is considered to be normal in people who are not taking anticoagulant medication. This value is higher in people who are taking anticoagulant medication because it takes longer for their blood to clot. An INR value of “2,” for example, means that the blood takes twice as long to clot. Different people may have different target INR values, mainly depending on their underlying medical condition.

The blood's clotting ability is first measured on the third day of taking the anticoagulants. That's how long it takes for the medication to start working. This blood test is done a few times per week at first. If the INR value hardly changes over several consecutive measurements, the blood tests can be done less frequently. If the target value is maintained over several months, it’s enough to then only check the values every four weeks.

The target INR range for people with atrial fibrillation is generally between 2 and 3. If the value is higher (e.g. 3.5) the drug dose is reduced. If it is lower (e.g. 1.5) the dose is increased a bit. Because the medication doesn't work immediately, it generally takes a few days for the INR value to change.

You don't always have to go to the doctor to have your blood tested. Instead, you can attend a patient education class to learn how to measure your INR values on your own. If the patient education is prescribed by a doctor, statutory health insurers usually cover the costs (in Germany). It makes sense to ask your health insurer about this beforehand. This kind of patient education is offered by doctor's practices and hospitals, for instance.

To monitor your blood values yourself, you simply have to prick your finger and smear a drop of blood onto a test strip. The test strip is then inserted into a special device that measures the INR value.

You are also shown how to adjust your dose yourself. People who monitor their blood's clotting ability themselves only have to go to the doctor's every few months.

The patient education doesn't only teach you how to monitor your own blood and adjust your medication. It also provides important information about many other aspects of treatment, like how your diet can influence your blood's clotting speed, interactions with other medications, and what you have to bear in mind if you're going to have an operation and are taking anticoagulants.

Many people who take anticoagulants prefer to self-monitor because it means that they're more flexible and have fewer check-ups at the doctor's. Studies have also shown that people who monitor their own blood are less likely to develop blood clots and resulting complications.

Some people are hesitant to monitor their own blood. Others aren't able to, for instance because they have poor vision. Then they can ask loved ones to help. Patient education classes to learn how to monitor blood and adjust medication can also be attended by loved ones.