Factor IX Assay Blood Test Marylebone
From 1 October 2026 — until then book at South Kensington or St Paul's. South Kensington · St Paul's
£147
+ £50 phlebotomy fee (per visit)
+ £50 phlebotomy (per visit)
Confidential Results
Secure online portal
Fast Results
5 days
Professional Service
Experienced phlebotomists
Wimpole Street, Marylebone (opening 1 October 2026)
Opening hours from 1 October 2026
- Monday
- 9am – 6pm
- Tuesday
- 9am – 8pm
- Wednesday
- 9am – 6pm
- Thursday
- 9am – 8pm
- Friday
- 8am – 5pm
- Saturday
- 10am – 4pm
- Sunday
- Closed
- Bond Street — about 6 minutes (Central, Jubilee & Elizabeth lines)
- Oxford Circus — about 7 minutes (Central, Bakerloo & Victoria lines)
Wimpole Street, Marylebone
From 1 October 2026 the Factor IX Assay can be arranged at Wimpole Street Medical & Dental for £147. A venous blood sample (citrate) is taken by a nurse or phlebotomist and sent to a UKAS-accredited partner laboratory, which quotes 5 days , Desc.: Should be sent to lab immidiately in red bag for this clotting and specialist haematology test. The laboratory report shows each value for blood clotting and hemophilia B against its reference range and is released to your portal; we do not interpret results, so take it to your GP or a clinician.
Factor IX Assay’s place in clotting and specialist haematology testing
- Sample
- venous blood sample (citrate)
- Laboratory turnaround
- 5 days , Desc.: Should be sent to lab immidiately in red bag
- Appointment
- 20 minutes
- Standard price
- £147 + £50 phlebotomy per visit
What Factor IX Assay measures
Laboratories file the Factor IX Assay under blood clotting, hemophilia B and christmas disease. The following sections set out how a clotting and specialist haematology test of this kind is measured and read.
Clotting tests measure how quickly blood forms a clot along different pathways — prothrombin time and INR, APTT, thrombin time and fibrinogen — and individual factor assays pinpoint which protein is short when a screening test is prolonged. Thrombophilia testing goes the other way, looking for a tendency to clot too readily through protein C, protein S, antithrombin, lupus anticoagulant and the Factor V Leiden and prothrombin gene variants. Specialist haematology in this group also includes haemoglobin electrophoresis for sickle and thalassaemia traits, von Willebrand studies, platelet function, blood group and antibody screens, and molecular tests used in the diagnosis and monitoring of blood cancers.
Who considers Factor IX Assay
- People often consider clotting tests if they bruise very easily, bleed for a long time after cuts or dental work, or have heavy periods since adolescence.
- A blood clot in the leg or lung at a young age, or several clots in the family, commonly leads to thrombophilia testing.
- Those on warfarin need INR monitoring, and people on newer anticoagulants occasionally need drug-specific anti-Xa levels.
- Couples from regions where sickle cell or thalassaemia are common may check carrier status before pregnancy.
- Recurrent miscarriage investigations frequently include antiphospholipid antibodies and lupus anticoagulant.
Preparing for your Factor IX Assay
- 1Anticoagulants such as warfarin, heparin and the direct oral agents alter most clotting tests; tell the nurse exactly what you take and when the last dose was.
- 2Thrombophilia testing is most reliable when you are well, not pregnant and at least three months from an acute clot or a course of anticoagulation.
- 3Oestrogen-containing contraception and HRT lower protein S; the result will be interpreted with that in mind.
- 4No fasting is needed, though a very fatty meal can interfere with some optical assays.
Sample for this test: venous blood sample (citrate).
Understanding your Factor IX Assay results
A prolonged clotting time can indicate a factor deficiency, an inhibitor, liver disease or anticoagulant effect, and mixing studies and factor assays help to separate these. A positive thrombophilia result may raise lifetime clot risk, but management depends on whether you have actually had a clot, so the finding is discussed with a haematologist rather than acted on in isolation. Haemoglobin electrophoresis reports the type of haemoglobin present and identifies carrier states relevant to family planning.
Coagulation results are strongly affected by medication, pregnancy and acute illness, and specialist haematology findings should be interpreted by a haematologist alongside your history.
Related areas of testing at Wimpole Street: full blood count, pregnancy-related tests, genetic testing, liver function.
Pricing
Factor IX Assay
Individual test
Phlebotomy Fee
Blood draw by qualified phlebotomist (per visit)
Total
£197Payment is collected at the clinic. The phlebotomy fee is charged once per visit, regardless of the number of tests booked.
From booking the Factor IX Assay to reading your result
- 1
Choose your test
Select the Factor IX Assay and any others you want run from the same visit. Until 1 October 2026 the identical test can be booked at South Kensington or St Paul’s.
- 2
Nurse-led sample
From 1 October 2026 the venous blood sample (citrate) is taken at 22 Wimpole Street, Marylebone by our nursing team, led by Precious Agbonmamwen, Registered Adult Nurse (NMC 20H1641E). Identity is checked and any preparation questions answered first.
- 3
UKAS-accredited laboratory
The sample travels to a UKAS-accredited partner laboratory, whose methods and reference ranges match those used across the NHS and private sectors.
- 4
Laboratory report to your secure portal
The laboratory report is released to your secure portal — typically from 24 hours; the laboratory quotes 5 days , Desc.: Should be sent to lab immidiately in red bag for this test. It shows each value against the reference range and flags anything outside it; discuss the report with your GP or a clinician.
Why test at Wimpole Street
Wimpole Street Medical & Dental opens at 22 Wimpole Street on 1 October 2026. Medical services are for patients aged 16 and over; registration with the CQC is in progress ahead of opening.
Wimpole Street, Marylebone (opening 1 October 2026)
- Bond Street — about 6 minutes (Central, Jubilee & Elizabeth lines)
- Oxford Circus — about 7 minutes (Central, Bakerloo & Victoria lines)
- Analysis is carried out by a UKAS-accredited partner laboratory, so methods and reference ranges match those used across the NHS.
- The same catalogue already runs at South Kensington and St Paul’s, so you can test now and move your records to Marylebone later.
- Self-referral: you choose the test and book directly — no GP referral is needed, and the laboratory report is yours to take to your GP or a clinician.
Other tests often considered alongside Factor IX Assay
- CD56Wimpole Street, Marylebone · from 1 October 2026
- Factor VII AssayWimpole Street, Marylebone · from 1 October 2026
- HaemoglobinWimpole Street, Marylebone · from 1 October 2026
- Porphyrin (Urine)Wimpole Street, Marylebone · from 1 October 2026
- Transferrin ElectrophoresisWimpole Street, Marylebone · from 1 October 2026
- Antithrombin Ill ActivityWimpole Street, Marylebone · from 1 October 2026
Frequently Asked Questions
A venous blood sample (citrate). A nurse or phlebotomist collects it at 22 Wimpole Street, Marylebone from 1 October 2026; the appointment allows time for identity checks and any preparation questions. The laboratory quotes 5 days , Desc.: Should be sent to lab immidiately in red bag for this test.
Ready to Book Your Test?
Wimpole Street opens 1 October 2026. Register your interest for the Marylebone diary, or book the same test now at South Kensington or St Paul's.
Important information about the Factor IX Assay at Wimpole Street
- Medical services at Wimpole Street Medical & Dental are for patients aged 16 and over.
- This is a self-referral service: you choose the test and book directly — no GP referral is needed.
- Nurse-led by Precious Agbonmamwen, Registered Adult Nurse (NMC 20H1641E), who oversees sample-taking standards, infection control and the patient pathway. The nursing team does not interpret results.
- A laboratory result is not a diagnosis and this page is not a substitute for medical advice. We do not provide clinical interpretation of results — please discuss your report with your GP or a clinician, particularly if a value is flagged or you have symptoms.
- CQC registration for Wimpole Street is in progress ahead of the opening on 1 October 2026; our South Kensington and St Paul’s clinics are CQC registered.
- Your results are held on a secure portal and treated as strictly confidential, except where disclosure is required by law.
- If you are seriously unwell, call 999. For urgent advice that is not an emergency, call NHS 111.
