Coupon Codes not valid for this testing. Fasting Required: No Lab: Quest Diagnostics Specimen: Blood Results: Average processing time 3-5 days Note: Result turnaround times are an estimate and are not guaranteed. Our reference lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance. Description: 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. Serum protein electrophoresis uses an electrical field to separate the proteins in the blood serum into groups of similar size, shape, and charge. Serum protein electrophoresis is most often done to help diagnose and monitor a wide variety of conditions. These include some forms of cancer, problems with the kidneys or liver, problems with the immune system, and conditions that lead to poor nutrition. Alternative Name(s): SPEP