Disorder Bleeding Time PT PTT Platelets Hemophilia A Normal Normal Elevated Normal Hemophilia B Normal Normal Elevated Normal Vitamin K deficiency Normal Elevated Normal/Elevated Normal Liver Disease Normal Elevated Normal/Elevated Normal/low Disseminated Intravascular Coagulopathy Elevated Elevated Elevated Very Low Heparin…
Pancytopenia is a complete blood count finding where all peripheral blood cell lineage counts are below the reference range Definition of terms Term Definition Bone marrow failure Bone marrow failure is a decrease in the production of one or more…
Aplastic anaemia is characterised by pancytopenia with a hypocellular bone marrow, in the absence of an abnormal infiltrate or bone marrow fibrosis. The Loss of haematopoietic stem cells (CD34+/CD38-) is a defining feature of aplastic anaemia. Classification of aplastic anaemia…
Polycythemia vera is characterised by peripheral erythrocytosis. It is commonly caused by a point mutation in JAK2. Thrombocytosis and leukocytosis can also occur in addition to erythrocytosis. The classic presentation is an unexplained high haemoglobin with low MCV and low…
Chronic neutrophilic leukaemia is a rare aggressive myeloproliferative neoplasm that is characterised by persistent mature neutrophils, granulocyte hyperplasia, and hepatosplenomegaly. It is associated with mutations in Colony Stimulating Factor-3 (CSF-3) receptors.
Mastocytosis is characterised by mast cell proliferation and accumulation within various organs, most commonly the skin. It is associated with mutations in KIT (a transmembrane tyrosine kinase receptor for SCF)
Essential thrombocythaemia is characterised by an increase in the number of circulating platelets, due to the mutations JAK2, CARL, or MPL (90%), which cause sustained proliferation of megakaryocytes. Patients have a persistently elevated platelet count (>450,000/uL) and splenomegaly, and frequently…
Primary myelofibrosis is characterised by the replacement of bone marrow by fibrous tissue. There are abnormal proliferating megakaryocytes and granulocytes that produce cytokines that stimulate fibrosis. The typical presentation is a patient with anaemia, teardrop RBCs, leukoerythroblastosis, and hepatosplenomegaly. No…
Polycythemia is a laboratory finding characterised by an increased number of RBCs and an accompanying elevation in haematocrit and haemoglobin concentration in the peripheral blood. It is commonly an incidental finding. Definition of terms Term Definition Relative polycythemia An isolated…