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Blood Tests > Coagulation (PT, aPTT, INR)

Coagulation (PT, aPTT, INR)

Price
£125

Turnaround

12 hours

Appointment

15 minutes

4.9

Rated 4.9 out of 5

4.7

Rated 4.7 out of 5

at a glance

Price: £125

Turnaround: 12 hours

Appointment: 15 minutes

4.9

Rated 4.9 out of 5

4.7

Rated 4.7 out of 5

Coagulation Tests Overview

Coagulation tests, which are PT, aPTT, and INR, are vital blood tests used to assess the efficiency of blood clotting.

These are critical tests to be carried out for patients on anticoagulant therapy. Over 6.4 million tests are carried out in the UK every year.

The test is used for diagnosing disorders in clotting, drugs causing blood thinning, and assessing the functioning of the liver.

Coagulation Screening Explained

Prothrombin Time (PT): This test is designed to measure the time it takes for blood to clot and to determine the functioning of some clotting factors or proteins produced in the liver.
Activated Partial Thromboplastin Time: The effectiveness of another group of clotting factors is assessed through this test.
International Normalised Ratio (INR): This is the standard version of the PT test. In short, the INR is a standardised unit that measures the time it takes for the blood to clot. It is particularly helpful in monitoring patients on anticoagulation therapy because it maintains their medication levels within proper ranges.

Why Are Coagulation Blood Tests Important?

Coagulation tests help diagnose blood disorders, such as haemophilia or von Willebrand disease, or problems that affect blood clotting within blood vessels .

Thus, if one has excessive bleeding, is prone to bruising, or suffers from unexplained blood clots, these tests will reveal the possible issues.

Because many of the clotting factors used by your body are manufactured in the liver, abnormalities of coagulation tests can give a hint towards any liver condition or damage, which requires further investigation.

When Should You Get Tested?

Coagulation tests may be necessary if you are:

Scheduled for surgery or a procedure that may cause bleeding.
On long-term anticoagulant therapy.
Suspected of having a blood clotting disorder or liver disease.
Experiencing symptoms like excessive bruising, bleeding gums, or blood in urine/stool.

Possible Results

The normal ranges for coagulation tests are as follows:

Prothrombin Time (PT): 11-13.5 seconds.
Activated Partial Thromboplastin Time (aPTT): 30-40 seconds.

International Normalised Ratio (INR): 0.8-1.2 for individuals not on anticoagulants and 2.0-3.0 for patients on warfarin.

Statistics

Of coagulation tests detect clotting disorders.

0 %

Of surgeries require coagulation screening.

0 %

Of UK adults require coagulation tests yearly.

0 %

Of abnormal INR results indicate liver issues.

0 %

Here Is How To Book Your Test

book online or call us

Use our online booking engine or book your test by giving us a call.

Choose your test type

On the online booking engine select the “appointment type” you need.

meet with our experts

You will be seen by one of our friendly phlebotomists or trained clinicians.

Procedure

Type of sample taken: Blood

Why Choose Walk In Clinic
for blood testing

No
Hidden Charges

Transparent fees. The price you see is the price you pay.

No GP consultation
needed

No GP appointment requirement for blood tests

Established
since 1998

Experienced doctors & a professional team.

Strictly
confidential

Your medical records are kept private at all times.

testimonials

Jooyoung Nam

10 September 2026

I had a very positive experience at this clinic for my blood test and the follow-up with the GP. I particularly appreciated the care and attention throughout the process, including the follow-up after my results. Thank you to the team for making the experience so reassuring. I would happily recommend this clinic.

Lucy Cropper

31 August 2026

I had a fantastic experience at the Harley Street clinic. Staff were very welcoming and professional and booked my second blood test here also.

Truman Packard

19 August 2026

The service was efficient, personable and very complete. The doctor who saw me was very good, patient and sensitive. I’ll be going back.

Sue Heald

11 August 2026

As an international visitor, I was very grateful for the prompt attention to my request for an appointment. Dr Ali was respectful and empathetic in regard to my condition and suggested further treatment, which I was able to organise for the next day. Both offices I attended treated me appropriately and I would recommend Harley Street Health Walk-in Clinics to anyone visiting London who requires medical attention.

Isabella Johnson

3 August 2026

Highly recommend City Walk-In Clinic Really pleased with my experience at City Walk-In Clinic. I booked a female hormone test because I wanted some answers about a few symptoms I'd been having, and the whole process was straightforward. The staff were welcoming, friendly and didn't make me feel rushed at all. The blood test was quick, and they explained everything clearly before taking the sample. My results came back sooner than I expected, and it was reassuring to have everything presented in a way that was easy to understand. I'd definitely use the clinic again and would recommend it to anyone looking for a private female hormone test. Professional service, lovely staff and an all round positive experience.

Anabella Styles

9 July 2026

I had a private gp appointment yesterday as my feet have been swelling every day over the past few days. So I booked an appointment with Dr Heather. Dr Heather explained the possible causes of the swelling, including the heat that we are currently experiencing in London. Recommended further investigation if the swelling persists, to identify the underlying issue rather than just making assumptions.

Mary Anne

3 July 2026

I have used City Walk In Clinic as my go to place for routine blood tests. My recent full health check gave my doctor some clues that i may be approaching my menopause era. So my doctor has recommended that i do some tests to find out if indeed i am entering perimenopause, as the symptoms are there. Will be having my tests in the next few weeks. So glad i had a full health check, because all these symptoms were driving me crazy.

Dona P

24 June 2026

Really good service throughout. Reception staff were welcoming and the blood test was efficient and quick. Highly recommended as blood tests can be booked on the day with results being sent very quickly.

A B

23 June 2026

Great location for blood tests if you want very fast results! I got my results the same day, highly recommend!

Grace Vizcaino

2 June 2026

Very good service at a very reasonable cost. Same day results, I do recommend this clinic and would certainly be using it again.

Shona McGovern

16 May 2026

I attended The Harley Street Walk/in centre in the City recently. I was able to book my appointment the day before for a blood test at a time that suited me. The booking process was straightforward. The doctor that conducted the venous draw was efficient and very pleasant. I have never had such a painless venous draw and I have had many! My appointment was at 5pm and I had my results before 8 am the following day. I will be very happy to book my tests here in the future. Thank you.

Monju Zaman

19 April 2026

Very easy to arrange the appointment with plenty of immediate availability. Very convenient location. Friendly medical associate who took my blood and results arrived very promptly, ie early the next day. Seamless experience.

Nat N

17 April 2026

Attentive, welcoming and professional staff in a great area which is easy to get to! I always feel like I'm in good hands

Abdalla Mohamud Mohamed

18 March 2026

I had a very good experience at the clinic. The staff were punctual friendly and professional. I had a blood test done and received the results quickly on the same day. I would definitely recommend visiting them.

Ena Quinn

9 March 2026

Speedy and efficient place for quick bloods. Results have been same day for me. Very friendly staff too which is always a bonus

Arthur Attwell

22 January 2026

Great experience. I was visiting London from abroad and I needed a blood test before travelling onward. I arrived without an appointment and was done in 20 minutes. The staff were all lovely. I received my test results by email the next morning.

Omar

19 January 2026

Really professional and friendly. They always provide their results quickly!

Antigoni S.

17 January 2026

Very good experience — all the staff were very polite, I was assisted immediately, and the results were available the same day. Thank you very much Private City Clinic!

Sheila Daley

31 December 2025

I wanted a cholesterol check up and chose this clinic because it seemed to offer a competitive price for a detailed report. And so it turned out to be. Received a prompt and professional service at a price that was significantly less than other nearby providers in central London. I have now used it twice and would definitely recommend.

JenniferP-344

18 February 2025

I appreciated the discreet and professional care during my sexual health test. The clinic made me feel safe and respected, and the results were delivered quickly and privately. Definitely recommend if you value confidentiality.

MichelleD-11

21 February 2024

I can't express enough how pleased I am with the Private Walk-in Clinic. As someone who values privacy and comfort, this clinic hits all the marks. The waiting areas are designed for relaxation, and the staff ensures confidentiality at every step.

Anonymously

4 December 2023

The Walk-In Clinic in central London exceeded my expectations in every way. Their attention to detail and commitment to tailored care for their patients truly sets them apart. The availability of evening appointments until 6:30 pm was a game-changer for someone like me juggling multiple commitments.

LunaW23

14 May 2021

They are so fast. One call and I am there in a few hours, always the same team and so polite and nice.

JuliaSf

14 October 2020

I hope these guys open up again soon because I really cannot stand anyone else around here. they were perfect for me for tests and consultations whenever I needed them

Emily-M

2 August 2019

i have used these guys many times in the last 6 years and its always very fast and professional. most tests are done in 24hours and they call you to explain the results. recommended if you gp (like mine) gives you an appointment in 4 weeks time.

pricing

Coagulation (PT, aPTT, INR) Blood Test

see other blood tests

Comprehensive Blood Profile

£79

Platinum Blood Profile

£229

Book Your Blood Test Today

We offer a wide range of private blood tests in London. Same-day appointments are available 5 days a week.

Specialist Medical Team

We work with experienced consultants & healthcare professionals who have received positive feedback from our patients, and with whom we have established long-term relationships.

Amin Ali

Medical Associate

Dr Heather Craig

General practitioner (GP)

Dr Kate Soffer

General practitioner (GP)

Dr Mohammad Mohseyni

Senior General practitioner

Dr Oluwaseyi Kayode

Medical Associate

Juhina Chameseddin

Medical Associate

Our Clinics

City Of London

Harley Street

fAQ

What’s the difference between inherited and acquired clotting disorders?

Inherited disorders are genetic and present from birth, such as haemophilia A/B, Factor V Leiden, or von Willebrand disease. Acquired disorders develop later in life due to conditions like liver disease, vitamin K deficiency, certain medications, or autoimmune diseases like lupus.

Can I have a normal coagulation test and still develop a clot or bleed?

Yes, it is possible, as some clotting or bleeding disorders may not show up on standard tests like PT or aPTT. For example, patients with platelet function disorders may have normal coagulation results. And individuals with genetic thrombophilia may also have normal test results but an increased risk of clotting. Therefore, if your symptoms persist, more specialised testing may be necessary.

Is a coagulation test the same as a full blood count (FBC)?

No, not at all. A coagulation test and a full blood count (FBC) are different tests with distinct purposes. For example, an FBC measures the levels of red cells, white cells, and platelets in your blood. Whereas, a coagulation test evaluates how quickly and effectively your blood forms clots.

Can medications affect my coagulation blood test results?

Yes, several medications can significantly influence your test results. These include anticoagulants, aspirin and NSAIDs, oral contraceptives or hormone replacement therapy, and even certain antibiotics, chemotherapy drugs, and herbal supplements. Therefore, it is essential to inform your healthcare provider about all medications and supplements you are taking before the test.

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