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Protein Electrophoresis Serum

Serum proteins have different net charges and can be separated by electrophoresis into several distinct bands. The band that migrates fastest toward the anode is albumin followed by alpha 1-globulin, alpha 2-globulin, beta globulin, and gamma globulins.  Protein concentrations may be altered as a result of different disease states.  Interpretation of serum protein electrophoretic patterns is helpful in diagnosing some diseases. The most commonly recognized electrophoretic patterns are acute inflammation, alpha-1 antitrypsin deficiency, chronic inflammation, cirrhosis, hypoalbuminemia, hypogammaglobulinemia, monoclonal gammopathy, polyclonal gammopathy and protein losing disorder.

Pattern	Protein Changes	Frequently Associated Diseases
Acute Inflammation	Normal or Decreased albumin Increased a1G &/or a2Globulin	Acute infection and inflammatory disorders
Chronic Inflammation	Normal or Decreased albumin Increased a1G or a2Globulin Increased gamma Globulin	Autoimmune diseases, chronic liver disease, chronic infection, cancer
Hypo- albuminemia	Decreased albumin	Metastatic cancer, CHF, malnutrition, protein losing disorders
Hypogamma- globulinemia	Normal or decreased albumin Decreased gamma Globulin	Lymphoproliferative disorders, inflammatory bowel disease, congenital immunodeficiencies
Polyclonal gammopathy	Increased gamma Globulin	Autoimmune disease, infections, Liver disease
Cirrhosis	Increased gamma Globulin Beta-gamma bridging	Cirrhosis
Protein losing disorder	Decreased albumin Decreased alpha 1Globulin Increased alpha 2Globulin Increased beta Globulin	Nephrotic syndrome,  exudative skin disorders,  gastroenterophathies,
Monoclonal gammopathy	Normal or Decreased albumin Increased gamma Globulin	Myeloma, macroglobulinemia, MGUS, CLL, lymphoma
Antitrypsin deficiency	absent alpha 1Globulin	Alpha 1 antitrypsin deficiency
Hyperbeta- globulinemia	Normal – Decreased albumin Increased beta Globulin	Hyperlipidemia, diabetes mellitus, iron deficiency anemia

 

SPE Interpretation Tips

• Albumin band often looks less intense on IFE compare to SPE, probably because it is incompletely fixed and elutes off the gel
• Bisalbuminemia has bicuspid albumin bands and can be inherited or acquired
• Bilirubin, heparin & antibiotic binding can cause slurring of albumin band
• Hemolysis causes decreased alpha-2 band (haptoglobin) and appearance of hemoglobin band between alpha-2 and beta-1 regions
• Transferrin is increased in iron deficiency anemia and estrogen therapy and may appear as a peak in the beta region
• C3 is labile & decreases with storage; accounting for much variation in beta-2 region
• Cryoglobulin precipitates at the application point and resembles a monoclonal band
• Fibrinogen migrates between beta-2 and gamma regions (close to application point) and is present in plasma or heparin contaminated specimens
• CRP and C3c are increased in inflammation and mimic a monoclonal band in the gamma region
• Oligoclonal bands with hypergammaglobulinemia & possibly beta-gamma bridging may be present in serum following antigenic stimulation to viral & bacterial infections, vaccines, autoimmune diseases and angioimmunoblastic lymphadenopathy.
• Oligoclonal bands with hypogammaglobulinemia may be seen in patients with bone marrow transplants, common variable immunodeficiency, and immunosuppressive therapy.
• Infections may cause transient monoclonal proteins
• Light chain disease can result in monoclonal kappa or lambda chains in serum and not in urine if light chains are polymerized
• Kappa chains usually stain more strongly than lambda chains
• Monoclonal bands in the beta region may indicate light chain disease, amyloidosis, heavy chain disease, IgD and IgE monoclonal gammopathies
• Gamma heavy chain disease can produce a relatively broad band anywhere from the alpha-2 through the gamma region
• Broader width of monoclonal bands may be related to amount of protein applied to gel or heterogeneity of monoclonal protein due to glycosylation. IgA monoclonal bands are usually broader than IgG
• Therapeutic monoclonal antibody therapy, such as daratumumab and elotuzumab, can produce small monoclonal bands in the gamma region <0.1 g/dL. Other commonly used therapeutic monoclonal antibodies (e.g., infliximab, rituximab, adalimumab, eculizumab, and vedolizumab) are usually not detected by serum protein electrophoresis.

Clues that a monoclonal band is unlikely to be due to a malignant clonal expansion include:

1. Acute phase pattern is present along with monoclonal band
2. Monoclonal band is transient & may evolve into an oligoclonal pattern
3. All immunoglobulin classes are elevated along with monoclonal
4. Slightly abnormal kappa to lambda ratio
5. Light chains are not detected in urine

Serum protein electrophoresis should be repeated in one year for asymptomatic patients with a monoclonal protein less than 1.5 g/dL and normal values of hemoglobin, calcium, and creatinine.  Electrophoresis should be repeated in two to three months if the monoclonal protein is between 1.5 and 2.5 g/dL.  Patients being treated for multiple myeloma, Waldenstrom’s macroglobulinemia or amyloidosis should be monitored at one-to-two-month intervals. 

Reference ranges using the Helena SPIFE 4000 Split Beta SPE system are:

 

Specimen requirement is a red top tube of blood.