What causes a polyclonal gammopathy result on serum protein electrophoresis (SPEP)?

Updated: Jul 31, 2019
  • Author: Sherilyn Alvaran Tuazon, MD; Chief Editor: Eric B Staros, MD  more...
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Infectious, Inflammatory or various reactive processes may be associated with a broad-based peak or band in the gamma region (Figure 4). This pattern suggests a polyclonal increase in immunoglobulins. Liver disease, autoimmune disease, chronic viral or bacterial infections and various malignancies may cause a polyclonal rise in the gamma fraction (see Table 2 below).

Polyclonal pattern serum protein electrophoresis ( Polyclonal pattern serum protein electrophoresis (SPEP).

Table 2. Diseases Associated with a Polyclonal Gammopathy (Open Table in a new window)



Liver disease

Cirrhosis, autoimmune or viral hepatitis

Connective tissue diseases

Rheumatoid arthritis, systemic lupus erythematosus, scleroderma, Sjogren syndrome


Bacterial: osteomyelitis, endocarditis, osteomyelitis

Viral: HIV/AIDS, hepatitis C, Epstein-Barr virus

Hematologic disorders/malignancies

Non-Hodgkin lymphoma, chronic lymphocytic leukemia, thalassemia, sickle cell anemia

Nonhematologic malignancies

Lung, ovarian, gastric malignancies, hepatocellular carcinoma

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