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Full Blood Count
Full Blood Count

Overview of Anaemia



  • Anaemia is a very common condition that may occur in the context of reduced red blood cell production, increased red blood cell production, or red blood cell loss.
    • Look For

    • Reduced serum haemoglobin (Hb) concentration
    • Reduced haematocrit (HCT) / packed cell volume (PCV)
    • Reduced red cell count (RCC)
    • Causes of Anaemia

    • Reduced RBC Production

    • Haematinic deficiency - B12, folate, iron
    • Bone marrow pathology - pure red cell aplasia, myelodysplastic syndrome, myelofibrosis, bone marrow metastasis
    • Endocrine - EPO deficiency, hypothyroidism
    • Anaemia of chronic disease (infection / inflammation / malignancy)
    • Sideroblastic anaemia
    • Thalassaemias
    • Increased RBC Destruction (Haemolysis)

    • Immune haemolysis - autoimmune, alloimmune, drug-induced
    • Red cell fragmentation - thrombotic microangiopathies, mechanical haemolysis
    • Intrinsic RBC disorders - enzymopathies, membranopathies, haemoglobinopathies
    • Hypersplenism
    • Other - infection, copper, lead, hypophosphataemia
    • RBC Loss

    • Trauma
    • Gastrointestinal bleed
    • Bleeding from another source e.g. urinary tract
    • Factitious

    • Dilutional - excess fluid administration, pregnancy

Microcytic Hypochromic Anaemia

    • Look For

    • Reduced serum haemoglobin, haematocrit and red cell count
    • Reduced MCV (<80fL)
    • Reduced MCH / MCHC
    • Causes of Microcytic Hypochromic Anaemia

    • Iron deficiency anaemia
    • Thalassaemia
    • Congenital sideroblastic anaemia
    • Anaemia of chronic disease
    • Lead poisoning
    • Hyperthyroidism

Normocytic Normochromic Anaemia

    • Look For

    • Reduced serum haemoglobin, haematocrit and red cell count
    • Normal MCV (80 - 100fL)
    • Normal MCH / MCHC
    • Causes of Normocytic Normochromic Anaemia

    • Dilutional - excess fluid administration, pregnancy
    • Acute haemorrhage
    • Chronic kidney disease
    • Anaemia of chronic disease (infection / inflammation / malignancy)
    • Pure red cell aplasia - Diamond-Blackfan syndrome, drugs, lymphoma, CLL, parvovirus B19
    • Bone marrow infiltration - myelofibrosis, bone marrow metastases
    • Early megaloblastic anaemia
    • Early iron deficiency anaemia
    • Haemolytic anaemia
    • Congenital sideroblastic anaemia

Macrocytic Hyperchromic Anaemia

    • Look For

    • Reduced serum haemoglobin, haematocrit and red cell count
    • Elevated MCV (>100fL)
    • Elevated MCH / MCHC
    • Causes of Macrocytic Hyperchromic Anaemia

    • Megaloblastic anaemia - B12 / folate deficiency, drugs
    • Myelodysplastic syndrome
    • Post splenectomy
    • Hypothyroidism
    • Chronic liver disease
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 Abramson NE, Melton BE. Leukocytosis: basics of clinical assessment. American family physician. 2000 Nov 1;62(9):2053-66. Aslinia F, Mazza JJ, Yale SH. Megaloblastic anemia and other causes of macrocytosis. Clinical medicine & research. 2006 Sep 1;4(3):236-41. Brass D, Mckay P, Scott F. Investigating an incidental finding of lymphopenia. BMJ. 2014 Mar 3;348:g1721.
Brodsky RA, Jones RJ. Aplastic anaemia. The Lancet. 2005 May 7;365(9471):1647-56.
Buchanan GR, DeBaun MR, Quinn CT, Steinberg MH. Sickle cell disease. ASH Education program book. 2004;2004(1):35-47.
Bunn HF. Pathogenesis and treatment of sickle cell disease. New England Journal of Medicine. 1997 Sep 11;337(11):762-9.
 Capsoni F, Sarzi-Puttini P, Zanella A. Primary and secondary autoimmune neutropenia. Arthritis research & therapy. 2005 Aug 31;7(5):208.
Galanello R, Origa R. Beta-thalassemia. Orphanet journal of rare diseases. 2010 Dec 1;5(1):11.
Gayathri BN, Rao KS. Pancytopenia: a clinico hematological study. Journal of laboratory physicians. 2011 Jan;3(1):15.
George JN, Aster RH. Drug-induced thrombocytopenia: pathogenesis, evaluation, and management. ASH Education Program Book. 2009 Jan 1;2009(1):153-8.
 Gibson C, Berliner N. How we evaluate and treat neutropenia in adults. Blood. 2014 Aug 21;124(8):1251-8. Griesshammer M, Bangerter M, Sauer T, Wennauer R, Bergmann L, Heimpel H. Aetiology and clinical significance of thrombocytosis: analysis of 732 patients with an elevated platelet count. Journal of internal medicine. 1999 Mar 1;245(3):295-300. Harrison CN, Bareford D, Butt N, Campbell P, Conneally E, Drummond M, Erber W, Everington T, Green AR, Hall GW, Hunt BJ. Guideline for investigation and management of adults and children presenting with a thrombocytosis. British journal of haematology. 2010 May 1;149(3):352-75. Hay D, Hill M, Littlewood T. Neutropenia in primary care. BMJ: British Medical Journal. 2014 Sep 11;349. Honda T, Uehara T, Matsumoto G, Arai S, Sugano M. Neutrophil left shift and white blood cell count as markers of bacterial infection. Clinica Chimica Acta. 2016 Jun 1;457:46-53. Insiripong S, Supattarobol T, Jetsrisuparb A. Comparison of hematocrit/hemoglobin ratios in subjects with alpha-thalassemia, with subjects having chronic kidney disease and normal subjects. Southeast Asian J Trop Med Public Health. 2013 Jul 1;44:707-11. Keohane C, McMullin MF, Harrison C. The diagnosis and management of erythrocytosis. BMJ. 2013 Nov 18;347:f6667. Kovalszki A, Weller PF. Eosinophilia. Primary Care: Clinics in Office Practice. 2016 Dec 1;43(4):607-17. Lawrie D, Coetzee LM, Becker P, et al. Local reference ranges for full blood count and CD4 lymphocyte count testing. South African medical journal. 2009 Apr; 99(4): p. 243.
Madu AJ, Ughasoro MD. Anaemia of chronic disease: an in-depth review. Medical Principles and Practice. 2017;26(1):1-9.
 McMullin MF. Diagnosis and management of congenital and idiopathic erythrocytosis. Therapeutic advances in hematology. 2012 Dec;3(6):391-8.
Nienhuis AW, Nathan DG. Pathophysiology and clinical manifestations of the β-thalassemias. Cold Spring Harbor perspectives in medicine. 2012 Dec 1;2(12):a011726.
 Pearson TC. Apparent polycythaemia. Blood reviews. 1991 Dec 1;5(4):205-13.
Perry M. Understanding blood results: the full blood count. Practice Nurse. 2012 Oct; 42(2): 12-17.
 Rose SR, Petersen NJ, Gardner TJ, Hamill RJ, Trautner BW. Etiology of thrombocytosis in a general medicine population: analysis of 801 cases with emphasis on infectious causes. Journal of clinical medicine research. 2012 Dec;4(6):415. Rothenberg ME. Eosinophilia. New England Journal of Medicine. 1998 May 28;338(22):1592-600. Roufosse F, Weller PF. Practical approach to the patient with hypereosinophilia. Journal of Allergy and Clinical Immunology. 2010 Jul 31;126(1):39-44. Schwartzberg LS. Neutropenia: etiology and pathogenesis. Clinical cornerstone. 2006 Jan 1;8:S5-11. Sharma S, Rose H. Incidentally detected thrombocytopenia in adults. Australian family physician. 2014 Oct 1;43(10):700. Siracusa MC, Kim BS, Spergel JM, Artis D. Basophils and allergic inflammation. Journal of Allergy and Clinical Immunology. 2013 Oct 31;132(4):789-801. Stemmelin GR, Doti CA, Shanley CM, Ceresetto JM, Rabinovich OM, Reparaz MA, Vukovic MG, Bullorsky EO. Smoking as a Cause for Mild Chronic Neutrophilia.