Protein Electrophoresis

Protein Electrophoresis (most commonly ordered as Serum Protein Electrophoresis or SPEP) is a lab test that measures specific groups of proteins in your blood liquid (serum) or urine.

It works by placing a biological sample into a gel matrix and applying an electric field. Because proteins carry net electrical charges based on their structure, they migrate through the medium at different speeds depending on their size, shape, and charge—sorting themselves into distinct visual bands.