Protein Electrophoresis Test Health Article

Definition

Electrophoresis is a technique used to separate the different components (fractions) of a mixture, such as proteins in a biological sample. Separation is based on differences in the charge (and sometimes size) of the molecules, which determines their rate of movement in an electric field. Serum protein electrophoresis is a screening test that measures the major blood proteins. Protein electrophoresis testing can also be performed on urine and cerebrospinal fluid (CSF) samples.

Purpose

Protein electrophoresis testing is used to evaluate, diagnose, and monitor a variety of diseases and conditions through examination of the amounts and types of protein in a blood, urine, or CSF specimen.

Precautions

Certain other diagnostic tests or prescription medications can affect the results of protein electrophoresis

tests. The administration of a contrast dye used in some other tests may falsely elevate apparent protein levels. Drugs that can alter results include aspirin, bicarbonates, chlorpromazine (Thorazine), corticosteroids, isoniazid (INH), and neomycin (Mycifradin). The total serum protein concentration may also be affected by changes in the patient's posture or by the use of a tourniquet during venipuncture.

Protein is less concentrated in urine and CSF than in blood. Urinary and CSF proteins must be concentrated before analysis, and the added sample handling can lead to contamination and erroneous results. In the collection of a CSF specimen, it is important that the sample not be contaminated with blood proteins that would invalidate the CSF protein measurements.