The serum protein electrophoresis (SPEP) test measures specific proteins in the blood to help identify some diseases. Proteins are substances made up of smaller building blocks called amino acids. Proteins carry a positive or a negative electrical charge, and they move in fluid when placed in an electrical field.
The protein electrophoresis test is often used to find abnormal substances called M proteins. The presence of M proteins can be a sign of a type of cancer called myeloma, or multiple myeloma. Myeloma affects white blood cells called plasma cells in the bone marrow.
The normal range for total protein is between 6 and 8.3 grams per deciliter (g/dL). This range may vary slightly among laboratories.