Going for a blood test re anticoagulants - Anticoagulation UK

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Going for a blood test re anticoagulants


I am currently building up 6-weeks of anticoagulant use so I will be able to have an operation on my heart without the risk of a clot getting to my brain. This is under a cardiologist consultant.

However my GP doctor has asked me to go for an electrolytes blood test at the local hospital.

These two items seem in conflict with one another as I would have to stop the anticoagulants before the blood test.

Any comments please

20 Replies

I had the u and e blood test and they told me I could just do my normal activities before the test nothing special to prepare or anything like fasting.

The blood tests are soon over although they aren't exactly nice to go through.

Best of luck!

Where you on anticoagulants?

I had blood clots in my lungs a couple of years ago and they said for me to stay on them indefinitely and I don't mind as I don't know I'm on rivaroxaban and just take it religiously daily and then live my life the way I want to and forget about it.

That's sensible. I'm just diagnosed with af and don't know what's going to happen. I'm getting terrible headaches and often am very tired in the daytime. Apparently these symptoms will fade as my body adapts to the drugs.

I hope!

I remember when I was first diagnosed with blood clots in my lungs and I had felt terrified as well as no one had explained and talked me through what was likely to happen.

I feel the communication in healthcare needs a great deal of improvement as currently it is rubbish!

Totally agree. At least we have the internet but it sometimes makes things worse. I didn't know af could possibly eventually lead to dementia.

If you don't mind my asking what illness leads to your blood clots or do they not know?

They weren't sure.

As far as I know you always stop anticoagulants before certain blood tests (ie out of routine) where they may affect the results ... and also before any surgery to reduce the bleeding

Ah I see. So I guess a standard test should be ok. If there is one place where they should be able to stop bleeding I guess it's a blood test clinic!

I'll ring the clinic tomorrow. I'm finding it's always worth asking on these forums first, helps, like your comments, to formulate the question.


From much experience of blood tests I can virtually guarantee the taking of blood will not be a problem! They just want the effects of the drug out of your system so they get a "true" analysis .... If they thought you were very high risk they'd have put you on alternative e.g. heparin injections (which apparently act in a different way - but don't ask me more coz not a doctor!)


Good morning. Just picked up your message. Hope the blood test goes okay and your results. Just let the phlebotomist know that you are taking an anticoagulant before they take the blood. You should be fine. It’s just if they have trouble getting the blood out or nick the tissue, they are prepared compared to someone who is not on anticoagulants- you more are more likely to bruise.

For your surgery you should have a letter telling you when to stop your anticoagulant. After your operation, you will be monitored and then assessed when you can restart your medicines. Ps I am a pharmacist x

Thanks for that interesting information.

I have decided to take a multi-channel approach I will ring the blood clinic and tell them I am fully anticoagulated and ask for their advice.

My consultant cardiologist has stated that he will not do cardioversion unless I have at least 6 straight weeks of anticoagulants.

That therefore is top priority and if it means I have to postpone the blood test then I will.

the request for the blood test came from my surgery by text with no information on why it was needed other than urea and electrolytes. They know I am on anticoagulants.

As to getting blood out of me it is very difficult the nurse at my surgery after about 6 attempts and badly bruising me gave up.

It will be much easier if I could contact my doctor to ask why he has asked for a blood test and can it be postponed.

I can do this is only via the surgery reception and it is difficult to explain to them such things.

When I had my first u and e test back in 2017 nothing was explained to me what it was for and why it was needed and I had been terrified!

If they had explained things and talked me through it perhaps I would have felt differently.


Don't take magnesium or other supplements for a fortnight before surgery. Even the most beneficial and helpful ones, such as vitamin C, may change the way you respond to the GA or some other drug, so this is the normal recommendation. It ensures your body is responding in just the way they expect. You can restart again two or three days later, or when you get home.

in reply to Polski

Oh. I'll have to research that daily supplements vitamins and minerals are an essential part of my diet.

in reply to Melbuckton

Then I doubt that stopping for two weeks will make much difference to you!

How’s it going Mel?

Cutting Tesco magnesium in two. Half a tablet plus 100mg from one a day multivitamins gives enough

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