[Chronic anemia: diagnostic tools and approach].

Anaemia is frequently encountered in daily practice. With full knowledge of its pathophysiology a rational classification is possible allowing a suitable approach for diagnostic investigations. In a first stage, the data provided by blood counts, erythrocyte constants and reticulocyte counts guide the diagnostic rationale. In cases with microcytic and hypochromic anaemia, measurement of ferritin level separates iron deficiency anaemia from the so-called "inflammatory" anaemias. A high number of reticulocytes points to haemolytic anaemia. Among the many causes of haemolysis, one must first look for autoimmune haemolysis. Elsewhere, the clinical context and morphological red cell abnormalities point to a hereditary disease affecting the erythrocyte membrane, enzymes or globin content. Although rare, microangiopathic anemia with schizocytosis and paroxysmal nocturnal haemoglobinuria must not be misdiagnosed. Bone marrow examination remains the clue in non-regenerative normochromic, normo- or macrocytic anaemias. In difficult cases, other investigations, such as cytogenetics, isotopic examination and progenitor culture, may help in characterizing the anaemia. Serum erythroproietin essays and plasma transferrin receptor counts will soon figure among the methods used to explore anaemias.