
Dr Karen Breen
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 - part of HCA Healthcare
Central London, 27 Tooley St,Medical insurances accepted
Credentials
Professional experience
- 26 years of experience
- Consultant haematologist, Guys' Hospital, Guy's and St Thomas Private Healthcare (2012 to present)
Subspecialties
- Abnormal full blood counts including anaemia and thrombocytopenia
- Anticoagulation management including the newer direct oral anticoagulants
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
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)
Prizes and awards
- Clinical Excellence Award (2017 and 2020)
- Quality in Care Anticoagulation Award (2015 and 2019)
Languages spoken
- English
- Spanish
Reviews
- Would you recommend this doctor?
- Treatment of the doctor
- Treatment of the staff
- Waiting time
- Condition of facilities
- 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.
- 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.
- Professional, caring , thorough and very understanding
- 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.
- 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
- 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.
- 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.