Gamma Globulin, SPEP (percent)
The share of your serum protein in the gamma zone on electrophoresis, mostly antibodies. Reported as a percent.
AI-drafted. Awaiting verificationLOINC 13983-2
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What it is
Protein electrophoresis uses an electric current to sort the proteins in your blood serum into groups. The gamma group sits at the end of the tracing and holds most of your antibodies, which are also called immunoglobulins. About 80% of it is IgG, with smaller shares of IgA and IgM. This result gives the gamma group as a percent of your total serum protein. A separate result gives the amount in g/dL.
Why it matters
The gamma share shows how much of your serum protein is antibody protein and what its pattern looks like. A broad, even rise often reflects long-running inflammation, infection or liver disease. A narrow spike can mean one group of plasma cells is making a single antibody (a monoclonal protein), so clinicians look at the shape of the tracing as well as the number. Because this is a share of the total, it can also move when another fraction changes. Your clinician reads this together with the rest of the pattern.
If it’s low
A lower gamma share means antibody protein makes up less of your serum protein. Many people just under the lower limit have no problem. A clearly low result can go with low antibody levels from a medicine, protein loss or a blood condition. Many other things can cause this, and your clinician can put it in context.
Common causes
- A result just under the lower limit, which happens in a small share of healthy people because ranges are set that way
- Medicines that suppress the immune system, such as rituximab, steroids and chemotherapy
- Protein loss through the kidneys (nephrotic syndrome) or the gut (protein-losing enteropathy)
- Blood cancers such as chronic lymphocytic leukemia or multiple myeloma, sometimes without any spike
- A primary antibody deficiency such as common variable immunodeficiency (uncommon)
- Malnutrition or severe burns
What can help
- Ask whether quantitative IgG, IgA and IgM would confirm a low antibody level
- Ask whether a medicine could be lowering it
- Ask whether urine protein or kidney tests are worth a look
If it’s high
A higher gamma share means antibody protein makes up more of your serum protein. Most often it is a broad rise caused by inflammation, infection or liver disease, and a fall in albumin can also push the share up. Less often it comes from one clone of plasma cells making a single antibody. Many other things can cause this, and your clinician can put it in context.
Common causes
- Long-lasting (chronic) infections, including viral hepatitis, HIV and tuberculosis
- Autoimmune and connective tissue conditions, such as lupus, rheumatoid arthritis or sarcoidosis
- Liver conditions, including cirrhosis, autoimmune hepatitis and alcohol-related liver disease
- Long-running inflammatory conditions, including inflammatory bowel disease and chronic lung conditions
- Blood and lymph conditions, such as lymphoma or leukemia
- A monoclonal gammopathy, such as MGUS, multiple myeloma, Waldenström macroglobulinemia or amyloidosis
What can help
- Ask whether the tracing shows a broad rise or a narrow spike
- Ask whether immunofixation or quantitative IgG, IgA and IgM would help
- Ask whether liver tests and inflammation tests fit with this result
Usual ranges
What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.
For adults: 11.1–18.8 %. Source: International Journal of General Medicine.
- Adults (this one applies)11.1–18.8 %
What can affect your result
- Inflammation and infection: a broad rise in the gamma band often follows them
- Other fractions: a share of the total moves when albumin or another band changes
- Medicines that suppress the immune system lower antibody levels
- Method: capillary and gel systems give different intervals
- A blood sample with hemolysis, or fibrinogen when plasma is used, can create a false band
- The result is a share of the total, so a change in another fraction (for example a fall in albumin) moves it even when the amount of antibody has not changed.
- A blood sample in which red cells broke open (hemolysis) can distort the tracing and create false patterns.
- Plasma instead of serum adds fibrinogen, which can show up as an extra band. ARUP does not accept plasma for this test.
- C-reactive protein sits between the beta and gamma zones, so a high CRP during acute illness can add to the apparent gamma band (AFP 2005).
- Certain medicines can affect protein results (MedlinePlus). Check with your clinician before changing any medicine.
- Some sources say you may be asked not to eat or drink for up to 12 hours before the draw (MedlinePlus), while ARUP lists no preparation. Follow the instructions from your lab.
Depends on the cause. A broad rise follows inflammation or infection and can take weeks to settle; a monoclonal protein changes slowly.
When to talk to a clinician
Talk with your clinician if your lab flagged this result, or if the report describes a narrow band or spike in the gamma zone. Let them know sooner about bone pain or back pain that has no clear cause, a fracture after a minor injury, numbness or tingling in your hands or feet, unusual tiredness, or repeated infections.
Questions you could ask
- How does the gamma share fit with my other protein fractions?
- Does the graph show a broad rise or a narrow spike?
- Could an infection, an inflammatory condition or a liver condition explain it?
- Would quantitative IgG, IgA and IgM or immunofixation add anything?
- Could one of my medicines or another condition be lowering my antibody level?
- Should we check IgG, IgA and IgM?
Questions people ask
How can I turn this percent into g/dL?
Multiply the percent by your total protein and divide by 100. For example, a 15% gamma share with a total protein of 7.0 g/dL is 1.05 g/dL.
Does a high gamma percent mean I have myeloma?
Usually not. A broad rise is more often caused by infection, inflammation or a liver condition, and a low albumin can also push the share up. A narrow spike is what prompts clinicians to look for a monoclonal protein, and further tests such as immunofixation are then used.
Why does my lab's range differ from the one shown here?
Labs use different instruments and set ranges from different groups of healthy people. Published ranges for the gamma share run from about 8% to 22%. Use the range printed on your own report first.
Show the science and sources
For clinicians and researchers
Immunoglobulins migrate mainly in the gamma region, and about 80% of the immunoglobulin in the gamma zone is IgG (Mayo); immunoglobulins can also be found across the rest of the tracing, and C-reactive protein sits between the beta and gamma zones (AFP 2005). A monoclonal protein appears as a sharp, well-defined band with a single heavy chain and a light chain, while a polyclonal rise is a broad, diffuse band (AFP 2005). A narrow spike can also appear in the beta or alpha-2 zones. Serum protein electrophoresis shows a spike in only about 82% of people with myeloma in one series, and about 10% of myeloma patients without a spike have hypogammaglobulinemia (AFP 2005), and ARUP notes immunofixation is more sensitive for small M-proteins. Quantitative IgG, IgA and IgM, not electrophoresis, are the direct way to measure each antibody class, and when a monoclonal protein sits on a polyclonal background, serum protein electrophoresis should be used to follow the monoclonal protein (Mayo). The percent result is the fraction of the integrated tracing, so it depends on the other fractions as well. The Sebia Capillarys package insert gives 11.1–18.8% for gamma (Bikila 2022 Table 4). Other published intervals for the gamma share include 9.3–20.4% (USA, Paragon gel), 7.9–18.3% (Belgium, Paragon), 8.0–18.8% (Belgium, Capillarys), 10.2–18.5% (France, Capillarys, men) and 12.40–21.66% (healthy adults in Addis Ababa, Capillarys), and the Addis Ababa study found no significant difference between men and women for gamma (Bikila 2022). g/dL = percent x total protein / 100, so the g/dL and percent results are separate markers. Intervals are method specific.
LOINC 13983-2 (primary). Specimen: serum.
Sources
- Establishment of Reference Intervals for Serum Protein Electrophoresis of Apparently Healthy Adults in Addis Ababa, Ethiopia, International Journal of General Medicine (2022)
- Protein Electrophoresis, Serum (test 0050640), ARUP Laboratories
- Protein electrophoresis - serum, MedlinePlus (National Library of Medicine) (2026)
- Understanding and Interpreting Serum Protein Electrophoresis, American Family Physician (2005)
- Immunoglobulin G (IgG), Serum (test ID IGG), Mayo Clinic Laboratories
- Immunoglobulin Replacement Therapy in Secondary Hypogammaglobulinemia, Frontiers in Immunology (2014)
- LOINC code lookup (NLM Clinical Tables), National Library of Medicine
AI-drafted. Awaiting verification. Last reviewed 2026-10-03. How we build and check these pages.