Rational diagnostic work-up of anemia

Abstract

Abstract Anemia is defined as a decrease in the hemoglobin concentration below the age- and sex-specific lower limit, established by WHO as 130 g/L in men and 120 g/L in women. In principle, there are many differential diagnoses which must be considered. The diagnostic evaluation furthermore is complicated by the fact that anemias are often multicausal. A rational evaluation of anemia should always take into account the epidemiological data and also the individual patient’s history. The classification according to the size and the hemoglobin content of the red blood cells based on the erythrocyte indices still plays a central diagnostic role. The worldwide most important cause of a hypochromic-microcytic anemia is iron deficiency. Anemia of chronic disease (ACD) and thalassemia are to be considered as differential diagnoses. Disorders of vitamin B12 and folic acid metabolism are clinically the most important causes of hyperchromic-macrocytic anemia. The normochromic-normocytic group includes most forms of anemias. In these cases one should not try to cover all possible causes by a fully comprehensive laboratory panel within the first blood sample already. It is more appropriate to proceed step-by-step to evaluate the most frequent and clinically most important reasons first. This especially applies to geriatric and multimorbid patients where the diagnostic effort must be adjusted to the individual needs and prognosis of the patient, not only from economical but also from ethical reasons. In unexplained anemias, consultation of a hematologist should be considered. In case of doubt, bone marrow biopsy is required to precisely evaluate the hematopoiesis and to exclude a hematological disorder.