A hemoglobin electrophoresis test helps measuring different types of hemoglobin in the bloodstream. Hemoglobin comes in many molecular forms, some normal and some abnormal. While the normal hemoglobin carries and releases oxygen efficiently, the abnormal hemoglobin doesn't. The electrophoresis process is based on the fact that hemoglobin types have different electrical charges. During the process, an electrical current is allowed to pass through the hemoglobin in a blood sample, causing the hemoglobin types to separate at different rates and form bands. By comparing the pattern formed with that of a normal blood sample, doctors can see and understand the types and quantities of hemoglobin present in the blood sample.