What Is PEP Lab & Diagnostic Testing?

Updated April 17, 2017

Protein electrophoresis (PEP) tests refer to lab tests used to screen and diagnose a variety of conditions. PEP tests may be performed on samples of blood serum (sometimes called SPEP) or urine (sometimes called UPEP).


Laboratory specialists analyse PEP tests by putting the urine or blood sample on special paper and sending an electrical current through the sample. The electrical current causes proteins to visibly band together.


SPEP labs measure several protein groups, such as alpha-1 globulin and gamma globulin, as well as total protein. Abnormal results indicate different conditions, depending on the protein or protein group. For example, decreased total protein may indicate malnutrition or cirrhosis. High levels of alpha-1 globulin proteins may indicate cancer or an inflammatory disease.


UPEP labs measure levels of albumin and globulins, two types of protein, in the urine. High levels of protein in the urine may indicate a variety of disorders, such as decreased kidney function, kidney failure, urinary tract infection or diabetic nephropathy.


Many medicines, including corticosteroids, salicylates, tolbutamide and chlorpromazine, may cause inaccurate PEP lab results. Do not stop taking prescription drugs without asking your doctor first.

bibliography-icon icon for annotation tool Cite this Article

About the Author

Rebekah Richards is a professional writer with work published in the "Atlanta Journal-Constitution," "Brandeis University Law Journal" and online at She graduated magna cum laude from Brandeis University with bachelor's degrees in creative writing, English/American literature and international studies. Richards earned a master's degree at Carnegie Mellon University.