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Protein Electrophoresis (Blood)

Does this test have other names?

Serum protein electrophoresis, SPEP

What is this test?

Protein electrophoresis is a test that measures specific proteins in the blood. The test separates proteins in the blood based on their electrical charge. The protein electrophoresis test is often used to find abnormal substances called M proteins. Protein electrophoresis also tests for other proteins and immunoglobulins. 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 protein electrophoresis test is also used to diagnose other conditions affecting the plasma cells. These include Waldenström macroglobulinemia, monoclonal gammopathy of undetermined significance (MGUS), and primary amyloidosis.

Protein electrophoresis can also be used to help diagnose:

  • Thyroid problems

  • Diabetes

  • Anemia

  • Liver diseases

  • Poor nutrition or inability to absorb nutrients

  • Certain autoimmune diseases 

Why do I need this test?

Your healthcare provider may recommend this test if he or she suspects that you have a condition affecting your plasma cells. These conditions may cause the following symptoms:

  • Unexplained weight loss

  • Bone pain

  • Fatigue

  • Weakness

  • Nausea

  • Constipation

  • Unusual thirst

  • Frequent urination

  • Frequent illness or fevers

  • Bones that fracture easily

  • Back pain

  • High levels of calcium in the blood

What other tests might I have along with this test?

Your healthcare provider may also order:

  • Urine protein electrophoresis

  • Serum immunofixation

  • Bone marrow biopsy

  • Immunotyping, to find what type of M proteins are present

  • Complete blood count

  • Blood calcium and electrolyte test

  • Kidney and liver blood tests

  • X-rays

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.

Serum proteins can be albumin or globulins. Globulins are divided into alpha-1, alpha-2, beta, and gamma globulins.

Normal levels are:


60% to 75% or 3.6 to 5.2 grams per deciliter (g/dL) (36-52 grams per liter -g/L)

Alpha-1 (α-1) 

1.7% to 5% or 0.1 to 0.4 g/dL (1 to 4 g/L)

Alpha-2 (α-2)

6.7% to 12.5% or 0.4 to 1 g/dL (4 to 10 g/L)

Beta (β)

8.3% to 16.3% or 0.5 to 1.2 g/dL (5 to 12 g/L)

Gamma (γ)

10.7% to 20% or 0.6 to 1.6 g/dL (6 to 16 g/L) 

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

The risks are very minor. The needle may feel uncomfortable or painful. You may experience bruising, soreness, or pain in your arm at the puncture spot. These symptoms usually go away soon after the test is over. 

What might affect my test results?

Your diet or lifestyle habits are not likely to affect the results of this test.

How do I get ready for this test?

You probably don't need to take special precautions before having this test. Your healthcare provider will tell you if you need to stop eating or drinking for a period of time before the test. Your provider will also tell you if you need to skip any of your regular medicines on the day of the test. Be sure to tell your provider about all medicines you are taking, including over-the-counter and prescription medicines, and any illicit drugs. Also mention any vitamins, herbs, or supplements that you take.

Medical Reviewers:

  • Freeborn, Donna, PhD, CNM, FNP
  • Hanrahan, John, MD