Hemoglobin electrophoresis is used to detect abnormalities in the shape and concentration of hemoglobin, the red blood cell protein used to transport oxygen. The test is usually ordered following abnormal blood count results (red blood cells, hemoglobin, mean corpuscular volume (MCV), etc.) or symptoms of anemia (fatigue, pale skin, etc.). Hemoglobin consists of 4 chains: 2 alpha chains and 2 beta chains. Alpha or beta thalassemia is a disorder associated with the underproduction of one of the subunits. The test is also used to identify the most common of the 700 abnormal forms of hemoglobin found worldwide, most of them extremely rare. All abnormal forms are associated with anemias of varying severity. Some hereditary disorders affecting hemoglobin are often found more frequently (but not exclusively) in geographically identifiable populations (Mediterranean region for thalassemia, Africa for hemoglobin S or Asia for hemoglobin E, etc.).
Hemoglobin electrophoresis results are interpreted by a hematologist and can indicate that only one of the two copies of the gene is abnormal (e.g., thalassemia trait) or both. Results are interpreted in light of the clinical context and blood count results. Other more detailed analyses may be suggested by the interpreting hematologist.