Hemoglobinopathy Information and Courses from MediaLab, Inc.

Hemoglobin electrophoresis is the movement of hemoglobin proteins in an electric field at a fixed pH.Because the various hemoglobins are comprised of different combinations of globin chains (normal or abnormal), they will demonstrate different degrees of mobility. Typically, when a thalassemia or hemoglobinopathy is suspected, an alkaline electrophoresis is performed which may be confirmed with acid electrophoresis.For an alkaline hemoglobin electrophoresis, a hemolysate is applied to cellulose acetate which is electrophoresed in a buffer at pH 8.4-8.6. At this pH hemoglobin proteins move from cathode to anode. The proteins are visualized by the application of a dye which also makes them measurable by densitometry.

This photograph of a peripheral blood smear from an 18-year-old North African woman with anemia reveals sickle cells. Target cells are not conspicuous. This shifts the diagnostic evidence away from HbSC disease. Cells tagged by arrows are variants of sickle cells. These may appear when multiple abnormal hemoglobin combinations are responsible for the clinical problem. The cell marked by the single arrow is an envelope formed not only in HbS disease but in HbC disease as well. Two arrows tag a blister cell, which, when seen in several fields, should prompt a hemoglobin electrophoresis to determine the presence of an undiagnosed hemoglobinopathy. Blister cells with fuzzy edged pseudo-vacuoles (see photo) are to be distinguished from the pseudo-vacuoles (blister)with razor sharp edges suggesting a microangiopathic state.

The family (cited in the previous case history) was from a region of Thailand where the physician knew HbE carriers are prevalent. Homozygous hemoglobin E is common in Southeast Asia and presents with very mild anemia and seldom requires transfusion. Over 30 million people in the world are HbE carriers, making this abnormal hemoglobin almost as common as HbS. Hemoglobin E is uncommon in North America and in Europe, but with changing immigration patterns, hemoglobinopathy E cannot be ignored. Peripheral blood smear findings of target cells, microspherocytes, red cell hypochromia, a few red blood cell fragments, and nucleated red blood cells require evidence from hemoglobin electrophoresis to establish a diagnosis. Clinically, a very important and severe syndrome is hemoglobin E/beta thalassemia in which there is hemolysis requiring repeated transfusions. The patient has a severe anemia, low MCV (50's), and high RBC. This is characteristic of Hgb E/beta thalassemia.