Hemoglobin concentration may be normal or decreased. The MCV may be decreased because of loss of hemoglobin from denaturation and pitting.
Blood film may show hypochromia, poikilocytosis, polychromasia, anisocytosis, and basophilic stippling.
Heinz bodies are commonly found in circulating red cells; after splenectomy they become more abundant.
Reticulocytosis is often disproportionate to the severity of the anemia, particularly when the abnormal hemoglobin has a high oxygen affinity.
Diagnosis is confirmed by demonstration of an unstable hemoglobin. This may be done by:
— Isopropanol precipitation test: a simple screening test that involves the incubation of the hemolysate with a 17 percent of isopropanol; hemolysates containing unstable hemoglobin variants form a precipitate, whereas a normal hemolysate remains clear.
— Heat denaturation test: cumbersome and usually not used.
— Heinz body detection: requires the incubation of erythrocytes ...