Anemia: An approach to evaluation, 2014

Anemia is very commonly encountered in general clinical practice among all age groups. The more commonly used way to classify anemia has been to categorize it as being microcytic (mean corpuscular volume [MCV] <80 fL), normocytic (MCV 80-100 fL), or macrocytic (MCV >100 fL), which in turn allows for a more practical way to attempt to come up with a cause for any decrease in hemoglobin. Microcytic anemias are usually due to iron deficiency (in turn, a result of a number of different etiologies ranging from decreased intake, malabsorption, or blood loss), hemoglobinopathies (thalassemic syndromes), and some cases of severe anemia resulting from chronic disease. Normocytic anemia is often a result of anemia of chronic disease, hemolysis, or secondary to bone marrow failure. Macrocytic anemias are frequently caused by deficiencies of folic acid and/or Vitamin B12, exposure to toxic agents like drugs that interfere with DNA metabolism and alcohol, as also bone marrow failure states, such as from myelodysplastic syndrome. A comprehensive history, physical examination, and directed laboratory evaluation will help to identify a specific cause for anemia.