- Stanley L Schrier, MD
Stanley L Schrier, MD
- Editor-in-Chief — Hematology
- Section Editor — Myeloproliferative Disorders; Red Blood Cell Disorders
- Professor of Medicine
- Stanford University School of Medicine
Microcytosis is a descriptive term for red blood cell (RBC) size smaller than the normal range. The causes are numerous, and the evaluation depends on a synthesis of clinical and laboratory information.
This topic discusses causes of microcytosis and microcytic anemia. Additional topics discuss the following:
●Macrocytosis/macrocytic anemia – (See "Macrocytosis/Macrocytic anemia".)
●General anemia evaluation
•Child – (See "Approach to the child with anemia".)To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
- Brugnara C, Mohandas N. Red cell indices in classification and treatment of anemias: from M.M. Wintrobes's original 1934 classification to the third millennium. Curr Opin Hematol 2013; 20:222.
- Saxena S, Weiner JM, Carmel R. Red blood cell distribution width in untreated pernicious anemia. Am J Clin Pathol 1988; 89:660.
- Harkins LS, Sirel JM, McKay PJ, et al. Discriminant analysis of macrocytic red cells. Clin Lab Haematol 1994; 16:225.
- Eldibany MM, Totonchi KF, Joseph NJ, Rhone D. Usefulness of certain red blood cell indices in diagnosing and differentiating thalassemia trait from iron-deficiency anemia. Am J Clin Pathol 1999; 111:676.
- Madan N, Sikka M, Sharma S, et al. Red cell indices and discriminant functions in the detection of beta-thalassaemia trait in a population with high prevalence of iron deficiency anaemia. Indian J Pathol Microbiol 1999; 42:55.
- AlFadhli SM, Al-Awadhi AM, AlKhaldi D. Validity assessment of nine discriminant functions used for the differentiation between iron deficiency anemia and thalassemia minor. J Trop Pediatr 2007; 53:93.
- Ferrara M, Capozzi L, Russo R, et al. Reliability of red blood cell indices and formulas to discriminate between beta thalassemia trait and iron deficiency in children. Hematology 2010; 15:112.
- Schoorl M, Schoorl M, Linssen J, et al. Efficacy of advanced discriminating algorithms for screening on iron-deficiency anemia and β-thalassemia trait: a multicenter evaluation. Am J Clin Pathol 2012; 138:300.
- Tonelli M, Sacks F, Arnold M, et al. Relation Between Red Blood Cell Distribution Width and Cardiovascular Event Rate in People With Coronary Disease. Circulation 2008; 117:163.
- Allen LA, Felker GM, Mehra MR, et al. Validation and potential mechanisms of red cell distribution width as a prognostic marker in heart failure. J Card Fail 2010; 16:230.
- Lippi G, Sanchis-Gomar F, Danese E, Montagnana M. Association of red blood cell distribution width with plasma lipids in a general population of unselected outpatients. Kardiol Pol 2013; 71:931.
- Grant BJ, Kudalkar DP, Muti P, et al. Relation between lung function and RBC distribution width in a population-based study. Chest 2003; 124:494.
- Garcez ME, Peres W, Salvador M. Oxidative stress and hematologic and biochemical parameters in individuals with Down syndrome. Mayo Clin Proc 2005; 80:1607.
- Kobayashi S, Moriya H, Aso K, Ohtake T. Vitamin E-bonded hemodialyzer improves atherosclerosis associated with a rheological improvement of circulating red blood cells. Kidney Int 2003; 63:1881.
- Patel HH, Patel HR, Higgins JM. Modulation of red blood cell population dynamics is a fundamental homeostatic response to disease. Am J Hematol 2015; 90:422.
- Lam AP, Gundabolu K, Sridharan A, et al. Multiplicative interaction between mean corpuscular volume and red cell distribution width in predicting mortality of elderly patients with and without anemia. Am J Hematol 2013; 88:E245.
- Patel KV, Ferrucci L, Ershler WB, et al. Red blood cell distribution width and the risk of death in middle-aged and older adults. Arch Intern Med 2009; 169:515.
- Perlstein TS, Weuve J, Pfeffer MA, Beckman JA. Red blood cell distribution width and mortality risk in a community-based prospective cohort. Arch Intern Med 2009; 169:588.
- Horne BD, May HT, Muhlestein JB, et al. Exceptional mortality prediction by risk scores from common laboratory tests. Am J Med 2009; 122:550.
- Jaiswal S, Fontanillas P, Flannick J, et al. Age-related clonal hematopoiesis associated with adverse outcomes. N Engl J Med 2014; 371:2488.
- Veeranna V, Zalawadiya SK, Panaich S, et al. Comparative analysis of red cell distribution width and high sensitivity C-reactive protein for coronary heart disease mortality prediction in multi-ethnic population: findings from the 1999-2004 NHANES. Int J Cardiol 2013; 168:5156.
- Ueda T, Kawakami R, Horii M, et al. High mean corpuscular volume is a new indicator of prognosis in acute decompensated heart failure. Circ J 2013; 77:2766.
- Poludasu S, Marmur JD, Weedon J, et al. Red cell distribution width (RDW) as a predictor of long-term mortality in patients undergoing percutaneous coronary intervention. Thromb Haemost 2009; 102:581.
- Kurt M, Tanboga IH, Buyukkaya E, et al. Relation of red cell distribution width with CHA2DS2-VASc score in patients with nonvalvular atrial fibrillation. Clin Appl Thromb Hemost 2014; 20:687.
- Güngör B, Özcan KS, Erdinler İ, et al. Elevated levels of RDW is associated with non-valvular atrial fibrillation. J Thromb Thrombolysis 2014; 37:404.
- Adamsson Eryd S, Borné Y, Melander O, et al. Red blood cell distribution width is associated with incidence of atrial fibrillation. J Intern Med 2014; 275:84.
- Providência R, Ferreira MJ, Gonçalves L, et al. Mean corpuscular volume and red cell distribution width as predictors of left atrial stasis in patients with non-valvular atrial fibrillation. Am J Cardiovasc Dis 2013; 3:91.
- Saliba W, Barnett-Griness O, Elias M, Rennert G. The association between red cell distribution width and stroke in patients with atrial fibrillation. Am J Med 2015; 128:192.e11.
- Kim J, Kim YD, Song TJ, et al. Red blood cell distribution width is associated with poor clinical outcome in acute cerebral infarction. Thromb Haemost 2012; 108:349.
- Aung N, Dworakowski R, Byrne J, et al. Progressive rise in red cell distribution width is associated with poor outcome after transcatheter aortic valve implantation. Heart 2013; 99:1261.
- Rezende SM, Lijfering WM, Rosendaal FR, Cannegieter SC. Hematologic variables and venous thrombosis: red cell distribution width and blood monocyte count are associated with an increased risk. Haematologica 2014; 99:194.
- Demir R, Saritemur M, Ozel L, et al. Red cell distribution width identifies cerebral venous sinus thrombosis in patients with headache. Clin Appl Thromb Hemost 2015; 21:354.
- Solak Y, Yilmaz MI, Saglam M, et al. Red cell distribution width is independently related to endothelial dysfunction in patients with chronic kidney disease. Am J Med Sci 2014; 347:118.
- Ujszaszi A, Molnar MZ, Czira ME, et al. Renal function is independently associated with red cell distribution width in kidney transplant recipients: a potential new auxiliary parameter for the clinical evaluation of patients with chronic kidney disease. Br J Haematol 2013; 161:715.
- Afonso L, Zalawadiya SK, Veeranna V, et al. Relationship between red cell distribution width and microalbuminuria: a population-based study of multiethnic representative US adults. Nephron Clin Pract 2011; 119:c277.
- Kim HM, Kim BS, Cho YK, et al. Elevated red cell distribution width is associated with advanced fibrosis in NAFLD. Clin Mol Hepatol 2013; 19:258.
- DeLoughery TG. Microcytic anemia. N Engl J Med 2014; 371:1324.
- Thompson WG, Meola T, Lipkin M Jr, Freedman ML. Red cell distribution width, mean corpuscular volume, and transferrin saturation in the diagnosis of iron deficiency. Arch Intern Med 1988; 148:2128.
- Seward SJ, Safran C, Marton KI, Robinson SH. Does the mean corpuscular volume help physicians evaluate hospitalized patients with anemia? J Gen Intern Med 1990; 5:187.
- Vegh AB, George KC, Lotfi-Emran S, et al. Total tryptase levels indicate risk for systemic reactions to rush immunotherapy and mast cell activation. Ann Allergy Asthma Immunol 2011; 106:342.
- Marsh WL Jr, Bishop JW, Darcy TP. Evaluation of red cell volume distribution width (RDW). Hematol Pathol 1987; 1:117.
- Camaschella C. How I manage patients with atypical microcytic anaemia. Br J Haematol 2013; 160:12.
- Athiyarath R, Arora N, Fuster F, et al. Two novel missense mutations in iron transport protein transferrin causing hypochromic microcytic anaemia and haemosiderosis: molecular characterization and structural implications. Br J Haematol 2013; 163:404.
- ASSESSMENT OF RBC SIZE
- MCV (cell volume)
- RDW (size variability)
- Peripheral blood smear review
- CAUSES OF MICROCYTOSIS
- Iron deficiency anemia
- Anemia of chronic inflammation
- Rare causes
- APPROACH TO THE EVALUATION
- Confirm microcytosis/microcytic anemia
- Eliminate iron deficiency and thalassemia
- Assess the likelihood of anemia of chronic inflammation
- Additional evaluations
- SOCIETY GUIDELINE LINKS
- SUMMARY AND RECOMMENDATIONS