Hematology — Find Specialists & Top Hospitals Worldwide | MyMedicPlus

Haematology is the branch of internal medicine devoted to the study, diagnosis, treatment, and prevention of diseases affecting the blood, bone marrow, and lymphatic system. Blood diseases encompass a vast spectrum ranging from common conditions such as iron deficiency anaemia and deep vein thrombosis to life-threatening conditions such as acute leukaemia and aplastic anaemia. Haematologists are uniquely positioned as both diagnosticians — interpreting complex laboratory patterns — and clinicians who manage patients through often prolonged and intensive treatment courses.

The specialty overlaps significantly with oncology. Haemato-oncology (or haematological oncology) is the subspecialty focused on blood cancers — leukaemias, lymphomas, multiple myeloma, and myeloproliferative disorders — which are among the most complex and rapidly evolving areas of cancer medicine. Haematologists in this domain supervise intensive chemotherapy regimens, immunotherapy, targeted molecular therapies, and allogeneic stem cell transplantation.

Haematology also encompasses the specialty of haemostasis and thrombosis, which manages patients with abnormal bleeding (haemophilia, von Willebrand disease, thrombocytopenia) and abnormal clotting (deep vein thrombosis, pulmonary embolism, antiphospholipid syndrome, inherited thrombophilia). Bone marrow transplantation and cellular therapy — including CAR-T cell therapy, a revolutionary treatment for certain leukaemias and lymphomas — represents the cutting edge of haematological medicine.

Red cell disorders form another major subspecialty: sickle cell disease and thalassaemia are the most common inherited haemoglobinopathies globally, requiring specialist management from haematologists with specific expertise in these conditions. Transfusion medicine — the safe provision of blood products and management of transfusion reactions — also falls within the broader haematological domain.

Haematologists manage a broad range of blood and bone marrow disorders:

• Iron deficiency anaemia: The most common cause of anaemia worldwide, resulting from chronic blood loss (gastrointestinal bleeding, menorrhagia), inadequate dietary intake, or malabsorption; haematologists investigate the underlying cause and oversee intravenous iron infusion for cases unresponsive to oral supplementation.
• Macrocytic anaemias (B12 and folate deficiency): Vitamin B12 deficiency (pernicious anaemia, dietary deficiency in vegans) and folate deficiency causing large, abnormal red blood cells; associated with neurological complications if untreated.
• Sickle cell disease: Autosomal recessive haemoglobinopathy causing abnormal sickle-shaped red blood cells leading to vaso-occlusive crises, acute chest syndrome, stroke, avascular necrosis, and organ failure; managed with hydroxyurea, exchange transfusion, and potentially curative stem cell transplantation.
• Thalassaemia (alpha and beta): Hereditary quantitative haemoglobin disorders ranging from mild trait (carrier state) to severe transfusion-dependent thalassaemia major; managed with regular blood transfusions, iron chelation, and bone marrow transplant in eligible patients.
• Immune thrombocytopenic purpura (ITP): Autoimmune destruction of platelets causing low platelet counts and bleeding risk; treated with steroids, intravenous immunoglobulin, romiplostim, eltrombopag, or splenectomy.
• Haemophilia A and B: Inherited deficiency of clotting factor VIII (haemophilia A) or factor IX (haemophilia B) causing prolonged bleeding after trauma or surgery; managed with recombinant factor replacement, emicizumab prophylaxis (for haemophilia A), and gene therapy (emerging).
• Deep vein thrombosis (DVT) and pulmonary embolism (PE): Pathological blood clots in the deep veins of the leg or in the pulmonary arteries; anticoagulation with direct oral anticoagulants (DOACs) is the cornerstone of management.
• Acute myeloid leukaemia (AML): Aggressive blood cancer of myeloid progenitor cells causing rapid marrow failure; requires intensive induction chemotherapy followed by consolidation or allogeneic stem cell transplantation.
• Chronic myeloid leukaemia (CML): BCR-ABL-driven chronic leukaemia now managed with tyrosine kinase inhibitors (imatinib, dasatinib, nilotinib) achieving deep molecular remission in most patients.
• Hodgkin lymphoma: Highly treatable lymphoma characterised by Reed-Sternberg cells, associated with EBV; treated with ABVD or BEACOPP chemotherapy with high cure rates.
• Non-Hodgkin lymphoma: A diverse group of B-cell, T-cell, and NK-cell lymphomas ranging from indolent (follicular lymphoma) to highly aggressive (DLBCL, Burkitt lymphoma); treatment ranges from observation to intensive immunochemotherapy and CAR-T cell therapy.
• Multiple myeloma: Plasma cell malignancy causing bone destruction, renal failure, hypercalcaemia, and anaemia; treated with proteasome inhibitors, IMiDs, daratumumab, and autologous stem cell transplantation.

Haematologists use specialised laboratory tests and clinical procedures to diagnose and treat blood disorders:

• Full blood count (FBC) with differential and blood film examination: The foundational haematological test measuring haemoglobin, white cell count (with differential cell counts), platelet count, and red cell indices; manual blood film examination identifies morphological abnormalities — blast cells, sickle cells, target cells, hypersegmented neutrophils — that automated analysers may miss.
• Bone marrow aspiration and trephine biopsy: Needle aspiration of bone marrow (usually from the posterior iliac crest) provides material for cytological examination, flow cytometry, and cytogenetics to diagnose leukaemia, lymphoma, aplastic anaemia, and other infiltrative disorders. Trephine biopsy provides a core of intact marrow for architectural assessment of fibrosis or infiltration.
• Flow cytometry and immunophenotyping: Automated analysis of cell surface markers on bone marrow or peripheral blood cells using fluorescence-labelled antibodies to characterise haematological malignancies, detect minimal residual disease, and immunophenotype lymphomas.
• Cytogenetics and molecular analysis: Karyotyping and fluorescence in situ hybridisation (FISH) detect chromosomal abnormalities prognostic in AML, CML, and lymphoma. Next-generation sequencing (NGS) panels identify somatic mutations guiding targeted therapy selection (e.g., FLT3, IDH1/2, NPM1 in AML; BCR-ABL in CML).
• Coagulation studies: Prothrombin time (PT/INR), activated partial thromboplastin time (APTT), thrombin time, fibrinogen, D-dimer, and mixing studies identify coagulation factor deficiencies and inhibitors. Specific factor assays (Factor VIII, IX, XI) confirm haemophilia diagnoses.
• Thrombophilia screening: Panel of tests for inherited (Factor V Leiden, prothrombin gene mutation, protein C, protein S, antithrombin III deficiencies) and acquired (antiphospholipid antibodies, lupus anticoagulant) risk factors for venous thromboembolism.
• Blood transfusion and transfusion reaction management: Safe administration of packed red cells, platelets, fresh frozen plasma, and cryoprecipitate; haematologists investigate and manage transfusion reactions including haemolytic reactions, transfusion-associated circulatory overload (TACO), and transfusion-related acute lung injury (TRALI).
• Stem cell transplantation coordination: Allogeneic (donor) and autologous (patient's own) haematopoietic stem cell transplantation for leukaemia, lymphoma, myeloma, aplastic anaemia, and haemoglobinopathies; involves myeloablative conditioning chemotherapy, stem cell infusion, and careful management of graft-versus-host disease (GVHD) and infectious complications.
• Therapeutic phlebotomy: Regular removal of blood (500 mL per session) to treat polycythaemia vera and hereditary haemochromatosis by reducing excess red cell mass or iron burden respectively.

Haematology referral is appropriate when laboratory abnormalities or clinical features suggest a primary blood disorder that requires specialist diagnostic evaluation or treatment.

Urgent or expedited referral is required for any suspicion of haematological malignancy: new lymphadenopathy (enlarged lymph nodes at multiple sites), unexplained splenomegaly, constitutional symptoms (drenching night sweats, >10% unintentional weight loss, fever of unknown origin) known as 'B symptoms' — these combinations suggest lymphoma or leukaemia requiring urgent bone marrow biopsy and staging. Anaemia with a haemoglobin below 7 g/dL, especially if symptomatic (severe breathlessness, chest pain, altered consciousness) requires urgent evaluation. Any patient with a markedly abnormal white cell count — particularly if blast cells are identified on blood film — requires same-day haematology consultation to exclude acute leukaemia.

Routine haematology referral is appropriate for: anaemia not adequately explained or not responding to iron, B12, or folate supplementation after 6–8 weeks; unexplained thrombocytopenia (platelet count below 100 × 10⁹/L) or thrombocytosis; recurrent unprovoked venous thromboembolism (DVT or PE) suggesting underlying thrombophilia; easy or spontaneous bruising with prolonged bleeding time suggesting a platelet or coagulation disorder; known sickle cell disease, thalassaemia, or haemophilia requiring ongoing specialist management; and elevated haemoglobin (erythrocytosis) or leucocytosis not explained by infection or inflammation, which may represent a myeloproliferative neoplasm.

Haematologists in the USA complete a 4-year medical degree (MD or DO) followed by a 3-year internal medicine residency, during which they develop clinical skills across all organ systems. After obtaining ABIM internal medicine board certification, physicians enter a 2–3 year haematology fellowship — or a combined 3-year haematology/oncology fellowship if they wish to practise haemato-oncology, which covers both blood cancers and solid tumour oncology within the same training programme.

During haematology fellowship, trainees develop expertise in: interpretation of complex haematological laboratory data (blood film morphology, bone marrow biopsy, flow cytometry, cytogenetics); management of benign haematological conditions (anaemias, haemostasis disorders, thrombosis); administration and monitoring of chemotherapy regimens for leukaemia, lymphoma, and myeloma; and coordination of allogeneic and autologous stem cell transplantation. Many fellows also conduct laboratory or clinical research contributing to the rapidly evolving evidence base for haematological treatments.

Board certification in haematology is conferred by the American Board of Internal Medicine (ABIM) through a subspecialty examination. Combined haematology/oncology certification requires passing a single examination covering both disciplines. Recertification every 10 years maintains contemporary competency in a field transformed by CAR-T cell therapy, bispecific antibodies, and molecular targeted therapies over the past decade.

Subspecialty training in bone marrow transplantation leads to separate certification. In the UK, haematology training runs for 7 years (ST3–ST8) under the JRCPTB, leading to CCT in Haematology; subspecialty training in bone marrow transplantation requires additional accreditation through the British Society of Blood and Marrow Transplantation (BSBMT).

Most haematology referrals are initiated by a primary care physician or emergency physician following abnormal blood test results or clinical findings. Verify ABIM board certification in haematology or haematology/oncology through the ABIM website. For malignant haematology — leukaemia, lymphoma, myeloma — seek care at a comprehensive cancer centre or academic medical centre with dedicated haematological oncology services, where clinical trial access, CAR-T cell therapy, and allogeneic stem cell transplantation programmes are available. Outcomes for allogeneic transplantation and complex haematological malignancies are demonstrably better at high-volume specialist centres.

For benign haematological conditions — anaemia, thrombosis, thrombocytopenia, haemophilia — community haematology practices associated with hospital laboratory services provide appropriate care for most patients, with complex cases referred to academic centres.

For your first appointment, bring all recent blood test results (particularly the full blood count and differential, blood film report, iron studies, vitamin B12, folate, and coagulation screen), prior bone marrow biopsy reports, and imaging results (CT scan, PET scan) if cancer staging has been initiated. Note any personal or family history of blood disorders, clotting problems, or haematological malignancy. Haematological conditions often require extended treatment relationships — bone marrow transplant recipients may be followed by their haematologist for 5 or more years post-transplant.