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Dr Karen BreenHaematology in Central London
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Dr Karen Breen

Haematology in Central London and SE1 South Bank London

MBBCh MD MRCPI FRCPath
GMC: 4773454

5.024reviewsReview

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Expert in:
Thrombosis
Blood clots
Bleeding disorders
Platelet disorders
Pulmonary embolism
Deep vein thrombosis (DVT)
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Professional statement

Dr Karen Breen is an experienced and renowned consultant haematologist practising at her private clinics in London. Her specialties include thrombosis, obstetric haematology, and clotting, bleeding, and platelet disorders. Currently, Dr Breen is practising at Guys' Hospital, a private healthcare clinic of Guys' and St Thomas' NHS Trust, in addition to London Bridge Hospital.


Dr Breen completed her basic medical training whilst in Ireland, achieving her MB BCh in 2000. She later received her membership with the Royal College of Physicians of Ireland before eventually receiving her fellowship with the Royal College of Pathology. Dr Breen received her postgraduate haematology speciality training mostly in Ireland. She later relocated to London to complete research on antiphospholipid syndrome which led to her receiving an MD in 2015.


Over the years, Dr Breen has maintained a strong interest in her research. She continues to conduct research on antiphospholipid syndrome and thrombosis. Presently, she is involved in several current clinical trials and translational research. Dr Breen has had her work published in various peer-reviewed journals. On a regular basis, Dr Breen lectures both nationally and internationally.

Clinics

London Bridge Hospital
  • London Bridge Hospital profile image

    London Bridge Hospital - part of HCA Healthcare

    Central London, 27 Tooley St,

    Medical insurances accepted

    I'm paying for myself
    Bupa
    AXA
    AVIVA
    Cigna
    WPA
    Simply Health
    Allianz

Credentials

Professional experience

  • 26 years of experience
  • Consultant haematologist, Guys' Hospital, Guy's and St Thomas Private Healthcare (2012 to present)
  • Consultant haematologist, London Bridge Hospital (present)
  • Clinical lead, Haemophilia and Thrombosis, Guys and St Thomas’ NHS Foundation Trust, London (2018 to present)
View more

Subspecialties

  • Abnormal full blood counts including anaemia and thrombocytopenia
  • Anticoagulation management including the newer direct oral anticoagulants
  • Blood Cancer
  • Coagulation disorders
  • Deep vein thrombosis (DVT)
  • Haemostasis
  • Obstetric haematology
  • Peri-operative management of clotting and bleeding disorders including during pregnancy
  • Pulmonary embolism
  • Thrombosis
  • Antiphospholipid syndrome (APS)
  • Thrombophilia
  • Covid associated thrombosis
View more

Professional memberships

  • Fellow, The Royal College of Pathology
  • Member, The Royal College of Physicians of Ireland

Education

  • MB BCh, Trinity College, Dublin (2000)
  • Membership, The Royal College of Physicians of Ireland
  • Haematology specialist registrar, HSE (2004 to 2009)
  • Fellowship, The Royal College of Pathology
  • MD, Trinity College, Dublin (2015)
View more

Teaching posts

  • Dr Breen is a recognised trainer by the General Medical Council.

Positions in organisations

  • Member, Trust Thromboprophylaxis and Thrombosis Committee, Guys' and St Thomas’ Foundation Trust

Publications and conferences

  • Dr Breen's research can be found on ResearchGate and King's College London research protal.
  • Doyle A, Hunt B, Sanderson B, Zhang J, Mak SM, Benedetti G, Breen K, Camporota L, Barrett N, Retter A. A Comparison of Thrombosis and Hemorrhage Rates in Patients With Severe Respiratory Failure Due to Coronavirus Disease 2019 and Influenza Requiring Extracorporeal Membrane Oxygenation. Crit Care Med. (2021)
  • Doyle AJ, Breen KA, Hunt BJ. Antiphospholipid Syndrome with Monoclonal Gammopathy-A Mechanism for Recurrent Thrombosis? Thromb Haemost. (2021)
  • Doyle AJ, Thomas W, Retter A, Besser M, MacDonald S, Breen KA, Desborough MJR, Hunt BJ. Updated hospital associated venous thromboembolism outcomes with 90-days follow-up after hospitalisation for severe COVID-19 in two UK critical care units. Thromb Res. (2020 Dec)
View more

Prizes and awards

  • Clinical Excellence Award (2017 and 2020)
  • Quality in Care Anticoagulation Award (2015 and 2019)
  • Prize for best speaker at MacDonald Obstetric Society meeting (2011)
  • Haematology Association of Ireland scholarship
View more

Languages spoken

  • English
  • Spanish
Registration number: 4773454

Reviews

All reviews are from real patients and have been verified by our Customer Service department to ensure they meet our guidelines. Rules of the service

24 reviews

5.0

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  • I recently saw Dr. Breen and had an excellent experience. She was calm, reassuring, and took the time to explain my blood results in incredible detail. Her clear, high-level analysis helped me fully understand my situation and put me completely at ease. I left feeling confident and well cared for, I highly recommend Dr. Breen to anyone seeking a knowledgeable and compassionate haematologist.
    6 April 2026

    N.L.

    Verified patient
  • Wanted to understand more about the blood clots in husband's lungs and likely treatment as the anti coagulation clinic wasn't very helpful. Gave a clear explanation of next steps. We had a follow up scan, this was expensive, by no means pushed by Dr Breen but we wanted to be sure that the clots have gone. We did a subject access request to get original the A&E scans to help the conversation - Dr Brean spotted an unrelated condition on the scan, which is now being treated. Would recommend.
    19 March 2026

    G.T.

    Verified patient
  • Professional, caring , thorough and very understanding
    27 November 2025

    I.F.

    Verified patient
  • Dr Karen Breen is a professional and caring doctor, and in my case, was extremely thorough with the investigations she felt were necessary for me to have in order to diagnose my medical condition. I was very happy and relieved to be under her care as I felt comfortable with her.
    22 September 2025

    J.B.

    Verified patient
  • I am really pleased I found Dr Breen after I was unhappy with treatment from another consultant. She got to the bottom of how my DVT and PE was caused very quickly and the care since has been brilliant. Dr Breen described everything clearly and I would really recommend her
    24 March 2025

    M.D.

    Verified patient
  • I find Dr Breen to be very easy to talk too as she puts her patient at ease immediately. I find her to be highly professional and knowledgable and have full confidence in her.
    16 May 2024

    C.M.

    Verified patient
  • 15 May 2024

    U.U.

    Verified patient
  • Great communication style and filled me with confidence when she spoke. Very clear in her responses to questions. All in all a very reassuring consultation and feel very lucky to have found Dr Breen.
    12 March 2024

    C.S.

    Verified patient
  • 5 March 2024

    Z.B.

    Verified patient
  • 4 March 2024

    A.N.

    Verified patient
View all reviews

Treatments

The doctor is expert in

Bleeding disorders

Blood clots

Deep vein thrombosis (DVT)

Platelet disorders

Pulmonary embolism

Thrombosis

The doctor also specialises in:

Anaemia

Antiphospholipid syndrome

Haemophilia

Low blood count

Purpura

Thrombocytopenia

Thrombophilia

Frequently Asked Questions

What is Dr Karen Breen's specialty?

Dr Karen Breen is a consultant specialising in Haematology, with extensive experience in assessing and treating patients within this field.

Which conditions and treatments does Dr Karen Breen specialise in?

Dr Karen Breen is a haematologist (Blood Specialist) who provides assessment and treatment for Thrombosis, Bleeding disorders, Pulmonary embolism, Platelet disorders, Deep vein thrombosis (DVT) and Blood clots. During your consultation, you will be informed of the most suitable options following a personalised evaluation.

How many years of experience does Dr Karen Breen have?

Dr Karen Breen has 26 years of professional experience as a consultant haematologist (Blood Specialist), providing specialist assessment and treatment in this medical field.

What do patients say about Dr Karen Breen?

Patients give a rating of 5.0 out of 5 to Dr Karen Breen, a score considered excellent. This average is based on 24 verified patient reviews, reflecting the experience of those who have attended an appointment.

Are Dr Karen Breen's reviews verified?

Yes. All Dr Karen Breen's reviews come from verified patients who have attended either an in-person or an e-Consultation appointment. We use a system that ensures authenticity and prevents fake reviews. Some profiles may also display reviews from other platforms, which follow their own verification policies, with the source always clearly indicated.

Where does Dr Karen Breen practise?

Dr Karen Breen practices in the following locations:

  • Central London at 27 Tooley St
  • SE1 South Bank London at Westminster Bridge Road, London

In-person consultations are available at these locations as a Haematology.

How can I book an appointment with Dr Karen Breen?

You can book an appointment with Dr Karen Breen directly from this page by selecting the time that suits you best. Alternatively, you can call the phone number shown if you prefer personalised assistance.

Does Dr Karen Breen see NHS patients?

Many specialists featured on Top Doctors also hold NHS positions. However, appointments arranged for Dr Karen Breen through this platform are private, either self-pay or covered by private medical insurance.

Does Dr Karen Breen offer private appointments?

Yes, Dr Karen Breen offers private appointments for patients seeking flexible and direct access to a consultant haematologist (Blood Specialist).

Does Dr Karen Breen offer online consultations?

Yes, Dr Karen Breen offers online consultations. You can book an appointment directly from this page by selecting the date and time that suit you best. Personalised assistance is also available by calling the number displayed on this page.

Does Dr Karen Breen accept insurance?

Dr Karen Breen works with the following private medical insurance providers: Bupa, AXA, AVIVA, Cigna, WPA, Simply Health, Allianz, CS Healthcare, Vitality, The Exeter Friendly, Pru Health, Groupama, April, Freedom, National Assurance, General Medical, Saga, Healix, Legal & General Insurance, Health-online, Benenden Health , Alliance Health Group, Police Mutual, Aetna, Tricare, Asia Medical Assistance, AIG, Health Now, Humanis, International SOS, Standard Life and Bupa Global. If your insurer is not listed, you may contact the practice directly to confirm your coverage.

What is Dr Karen Breen's availability?

Dr Karen Breen's availability depends on the appointment slots open at any given time. On this page, you can check current availability, and if no slots are shown, you can request an appointment or contact the practice directly.

What payment methods does Dr Karen Breen offer?

You can pay for your consultation with Dr Karen Breen using the following methods: Self-paying or Prepaid.

What languages does Dr Karen Breen speak?

Dr Karen Breen is a haematologist (Blood Specialist) who offers consultations in English and Spanish.

How is Dr Karen Breen selected to appear on this platform?

All doctors listed on Top Doctors, including Dr Karen Breen, undergo our rigorous selection process. Only one in five specialists meets the required standards to be included.
Discover Top Doctors' rigorous medical selection process.
The doctor, or where applicable the hospital or medical centre in which the doctor provides services, undertakes to keep the information relating to the prices of services published on their profile on the Top Doctors platform up to date at all times, ensuring that such prices correspond to those effectively charged to patients. In the event of any discrepancy between the published price and the price ultimately charged to the patient, the doctor and/or the relevant hospital or medical centre shall be solely liable towards the patient and towards Top Doctors for any claim or financial difference arising therefrom.

Request now: The appointment management service is free

London Bridge Hospital - part of HCA HealthcareCentral London, 27 Tooley St,
Payment methodSelf-paying
Face-to-faceFirst visit Haematology
£250

This doctor hasn't published their schedule yetTo request an appointment, click here.

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