Anticoagulation service

To ensure your anticoagulation therapy is working well, we will monitor it with regular blood tests. These tests check your INR (International Normalised Ratio). You may have a blood sample taken from a vein (venous sample) or by finger-prick. Venous samples are available at most GP practices and locations like West Suffolk Hospital, Newmarket Hospital, and Sudbury Community Health Centre (for booking details, see below).

We also offer finger-prick testing at West Suffolk Hospital and Newmarket Hospital for those appropriate for those type of testing Contact us for more information about attending these clinics.

How to book a blood test

To book an appointment at one of the following locations, please visit our booking page:

• West Suffolk Hospital (Bury St Edmunds)

• Mildenhall Health Centre

• Newmarket Community Hospital

• Sudbury Health Centre

Book your appointment here.

After each INR test, we will send you a letter with your new warfarin dosage advice. These letters are sent by first-class post, so you should receive your letter soon after your test. If you do not receive it within three working days, please contact us. The letter will include your new dosage advice and any important instructions. Please read it carefully and follow the advice exactly.

The letter will also include a request form for your next blood test. Please give this form to the person taking your blood sample. Make sure you answer all the questions on the form each time you have a test.

If we need to make an immediate change to your dosage, we will call you after your INR test please note we will call you from a withheld number. We may also call you if we need to discuss any details on your request form. Please make sure we can contact you by phone on the day of your blood test. Let us know immediately if your contact details change.

Starting or stopping another medicine while taking warfarin can affect your INR. You should have an INR test one week after any medication change. If you start antibiotics, you should have an INR test 3-4 days after starting them, as they can affect INR quickly.

Illness can also change your INR, especially if you have diarrhoea, vomiting, or a loss of appetite. If you are unwell for more than a few days, you should have an INR test.

You do not need to contact us if you are having an INR test due to medication changes or illness, but please note the medicine name or illness details and the start date on your INR request form.

Bleeding is a common side effect of warfarin. You should seek medical help if you experience:

• Blood in your urine or stool

• A nosebleed lasting more than 10 minutes

• Bleeding gums

• Coughing or vomiting blood

• Unusual headaches

• Severe bruising

• Heavy bleeding during your period or any other vaginal bleeding

You should seek urgent medical help if you:

• Have a fall or accident

• Have a significant blow to your head

• Cannot stop any bleeding