Hematology (BE: haematology) is the branch of pathology, clinical laboratory medicine, internal medicine, and pediatrics that is concerned with the study of blood, the blood-forming organs, and blood diseases. Hematology includes the study of etiology, diagnosis, treatment, prognosis, and prevention of blood diseases. The lab work that goes into the study of blood is perfomed by a Medical Technologist.
Blood diseases affect the production of blood and its components, such as blood cells, hemoglobin, blood proteins, the mechanism of coagulation, etc.
Hematologists
Medical doctors who work in hematology are known as hematologists. Their routine work may range from the management of the hematology laboratory, work at the microscope viewing blood films and bone marrow slides, interpretation of various hematological test results, care of in-patients and care of out-patients.
Hematologists may specialise further or have special interests, for example in:
* treating bleeding disorders such as hemophilia
* treating hematological malignacies such as lymphoma and leukemia (onco hematology)
* treating hemoglobinopathies
* in the science of blood transfusion and the work of a blood bank
(Hema- means blood in root words, -ology means the study {science} of.[refering to the first root word, as in biology, with bio- meaning life and, of course , -ology meaning the study {or science} of])
Common Hematology Lab Tests
In a clinical laboratory the hematology department performs several medical tests on blood. The main test is a complete blood count (CBC). Other tests are reticulocyte, sedimentation rate, white blood cell count, platelet count, red blood cell count, and more. Coagulation is a subspecialty of hematology. General tests in coagulation are the prothrombin time (PT) and partial thromboplastin time (PTT).
Hematology as basic medical science
* Blood
o Venous blood
o Venipuncture
o Hemopoiesis
o Blood tests
o Cord blood
* Red blood cells
o Erythropoiesis
o Erythropoietin
o Iron metabolism
o Hemoglobin
o Glycolysis
o Pentose phosphate pathway
* Reticuloendothelial system
o Bone marrow
o Spleen
o Liver
* Lymphatic system
* Blood transfusion
o Blood plasma
o Blood bank
o Blood donors
o Blood groups
* Haemostasis
o Coagulation
o Vitamin K
* Complement system
o Immunoglobulins
Classification of hematology diseases
* Hemoglobinopathies (congenital abnormality of the hemoglobin molecule or of the rate of hemoglobin synthesis)
o Sickle-cell disease
o Thalassemia
o Methemoglobinemia
* Anemias (lack of red blood cells or hemoglobin)
o Iron deficiency anemia
o Megaloblastic anemia
+ Vitamin B12 deficiency
# Pernicious anemia
+ Folate deficiency
o Hemolytic anemias (destruction of red blood cells)
+ Genetic disorders of RBC membrane
# Hereditary spherocytosis
# Hereditary elliptocytosis
+ Genetic disorders of RBC metabolism
# Glucose-6-phosphate dehydrogenase deficiency (G6PD)
# Pyruvate kinase deficiency
+ Immune mediated hemolytic anaemia (direct Coombs test is positive)
# Autoimmune hemolytic anemia
* Warm antibody autoimmune hemolytic anemia
o Idiopathic
o Systemic lupus erythematosus (SLE)
o Evans’ syndrome (antiplatelet antibodies and haemolytic antibodies)
* Cold antibody autoimmune hemolytic anemia
o Idiopathic cold hemagglutinin syndrome
o Infectious mononucleosis
o Paroxysmal cold hemoglobinuria (rare)
# Alloimmune hemolytic anemia
* Hemolytic disease of the newborn (HDN)
o Rh disease (Rh D)
o ABO hemolytic disease of the newborn
o Anti-Kell hemolytic disease of the newborn
o Rhesus c hemolytic disease of the newborn
o Other blood group incompatibility (RhC, Rhe, RhE, Kid, Duffy, MN, P and others)
# Drug induced immune mediated hemolytic anaemia
* Penicillin (high dose)
* Methyldopa
+ Hemoglobinopathies (where these is an unstable or crystaline hemoglobin)
+ Paroxysmal nocturnal hemoglobinuria (rare acquired clonal disorder of red blood cell surface protiens)
+ Microangiopathic hemolytic anemia
o Aplastic anemia
+ Fanconi anemia
+ Diamond-Blackfan anemia
+ Acquired pure red cell aplasia
* Decreased numbers of cells
o Myelodysplastic syndrome
o Myelofibrosis
o Neutropenia (decrease in the number of neutrophils)
o Agranulocytosis
o Glanzmann’s thrombasthenia
o Thrombocytopenia (decrease in the number of platelets)
+ Idiopathic thrombocytopenic purpura (ITP)
+ Thrombotic thrombocytopenic purpura (TTP)
+ Heparin-induced thrombocytopenia (HIT)
* Myeloproliferative disorders (Increased numbers of cells)
o Polycythemia vera (increase in the number of cells in general)
o Leukocytosis (increase in the number of white blood cells)
o Thrombocytosis (increase in the number of platelets)
o Myeloproliferative disorder
* Hematological malignancies
o Lymphomas
+ Hodgkin’s disease
+ Non-Hodgkin’s lymphoma
+ Burkitt’s lymphoma
+ Anaplastic large cell lymphoma
o Myelomas
+ Multiple myeloma
+ Waldenström macroglobulinemia
o Plasmacytoma
o Leukemias
+ Acute lymphocytic leukemia (ALL)
+ Chronic lymphocytic leukemia (CLL)
+ Acute myelogenous leukemia (AML)
+ Chronic myelogenous leukemia (CML)
+ Hairy cell leukemia
* Coagulopathies (disorders of bleeding and coagulation)
o Thrombocytosis
o Recurrent thrombosis
o Disseminated intravascular coagulation
o Disorders of clotting proteins
+ Hemophilia
# Hemophilia A
# Hemophilia B (also known as Christmas disease)
# Hemophilia C
+ Von Willebrand disease
+ Disseminated intravascular coagulation
+ Protein S deficiency
+ Antiphospholipid syndrome
o Disorders of platelets
+ Thrombocytopenia
+ Glanzmann’s thrombasthenia
+ Wiskott-Aldrich syndrome
* Miscellaneous
o Haemochromatosis
o Asplenia
o Hypersplenism
+ Gauchers disease
* Haemotological changes secondary to non-haemotological disorders
o Anemia of chronic disease
o Infectious mononucleosis
o AIDS
o Malaria
o Leishmaniasis
Tests
Tests used in the investigation of haematological problems include:
* Full blood count
* Erythrocyte sedimentation rate (ESR)
* Blood film
* Bone marrow biopsy
* Coombs test
* serum Ferritin level
* Vitamin B12 and Folate levels
* Prothrombin time
* Partial thromboplastin time
* Protein electrophoresis
* Hemoglobin electrophoresis
* D-dimer
Treatments
Treatments include:
* Diet advice
* Oral medication – tablets or liquid medicines
* Anticoagulation therapy
* Intramuscular injections (for example, Vitamin B12 injections)
* Blood transfusion (for anemia)
* Venesection (for iron overload or polycythemia)
* Bone marrow transplant (for example, for leukemia)
* Chemotherapy (for example, for leukemia)
* Radiotherapy (in decline, for example, for leukemia)