What is a Coagulation Screen, and why has someone asked you for one?

A Coagulation Screen checks how well your blood clots. It measures four things: Prothrombin Time, INR, Activated Partial Thromboplastin Time and Fibrinogen. Together they show whether clotting is working normally.

Most people who book this in Plymouth have been asked for it by someone else. Usually that’s a surgeon, a dentist or a private clinic wanting clotting checked before a procedure. If that’s you, there’s no GP referral needed, and results come back the next working day.

Why this test matters

Clotting is a chain reaction. A dozen proteins have to activate in the right order, and if any step is slow or something is missing, blood takes longer to clot than it should. Most of the time you’d never know. It tends to show up only when something challenges it, like surgery or a dental extraction.

That’s why clinics ask for clotting studies beforehand. They don’t necessarily suspect a problem. It’s simply far easier to plan around one before a procedure than to deal with it during.

What this test measures

The four markers look at clotting from different angles. Two measure speed along different pathways, one standardises that speed so results can be compared between laboratories, and one measures the material a clot is built from.

Who should get this test?

This test suits a fairly specific set of situations. If yours isn’t among them, have a word with us before booking. There’s no sense paying for the wrong test.

• A surgeon, dentist or private clinic has asked for clotting studies before a procedure
• You bruise very easily, or bleed for longer than seems normal from small cuts
• Frequent nosebleeds, bleeding gums, or unusually heavy periods
• A family history of a bleeding disorder such as Haemophilia or Von Willebrand disease
• You are about to start an anticoagulant and want a baseline beforehand
• You are monitoring known Liver disease, where Prothrombin Time is used as a marker of Liver function

What your results mean

Your results come back as numbers alongside the laboratory’s reference ranges, with a clinical sumarry if neeeded, explaining them. For most people having this before a procedure, everything sits within range and the commentary says so. That’s what the referring clinic needs to see.

If something falls outside the range, what it means depends on context: what medication you take, whether you have Liver disease, whether you’ve been unwell recently. One prolonged result is a reason to look further. We’ll explain what we can see and what would sensibly come next, which might mean going back to whoever requested the test, or a referral to a haematologist.

Blood tests give information. They don’t, by themselves, diagnose a condition.

What happens at your appointment

You’ll be seen at Tor Clinical Rooms in Estover, Plymouth. The draw takes a few minutes and no fasting is needed, so eat and drink normally beforehand.

One practical point specific to this test. Clotting samples go into a tube holding a fixed amount of anticoagulant, and the ratio of blood to anticoagulant has to be exact. The tube has a fill line and the blood must reach it. If it under-fills, which happens occasionally when a vein is difficult, the laboratory can’t run the sample reliably and we’d take another there and then. A redraw on the day beats a result we don’t trust.

Samples go to our UKAS-accredited laboratory partner by tracked post, and results are back the next working day. All appointments must be booked in advance.

Frequently asked questions

Does this test check whether I have a blood clot?

No. This test measures how well your blood forms a clot. Whether a clot has already formed somewhere is a different question. The test used to help rule out a deep vein thrombosis or a pulmonary embolism is a D-dimer, and it isn’t included here. If you’re worried about a clot, seek urgent medical attention rather than booking a blood test.

I take Warfarin. Should I book this to check my INR?

Almost certainly not. If you’re on Warfarin, your INR monitoring is free through your anticoagulation clinic or GP practice, and they hold the record of your previous readings. That record is what makes each new number mean anything. Paying privately for a single INR gives you a figure with nothing to read it against. The exception is needing a result urgently for a procedure and not being able to get one in time the usual way. If that’s your situation, get in touch and we’ll talk it through.

I take Apixaban or Rivaroxaban. Do I need INR checks?

No. The newer anticoagulants, sometimes called DOACs, don’t need routine INR monitoring. They can still affect the results of this test, so tell us what you take when you book, but you don’t need regular clotting checks the way Warfarin patients do.

Is this a test for inherited clotting disorders?

No. A thrombophilia screen looks for inherited tendencies to clot, such as Factor V Leiden or protein deficiencies, and uses different tests from these four. Recurrent miscarriage, clots at a young age or a strong family history of clotting all point towards that different investigation. Contact us and we’ll advise on what’s appropriate and what we can arrange.

Will the clinic that asked for this accept the results?

In our experience, yes. Samples are analysed by a UKAS-accredited laboratory and results come with the laboratory’s own reference ranges. You’ll get them by email in a form you can forward. If the clinic has asked for anything beyond these four markers, send us the request and we’ll confirm whether we can cover it before you book.

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