Serum protein electrophoresis is mainly used for the diagnosis and monitoring of patients with monoclonal gammopathies.
Total serum proteins consist of albumin and globulins. Albumin, which is synthesized in the liver, is essential for maintaining oncotic (osmotic) plasma pressure. It carries various molecules in the body, such as bilirubin, fatty acids, medicines, and hormones, which bind to albumin while in the bloodstream.
There are three main types of globulins: alpha-, beta- and gamma-globulins. Alpha-globulins are synthesized in the liver and include alpha1-globulins, such as alpha1 antitrypsin, alpha-fetal globulin (aFP), thyroxine-binding globulin, and alpha2-globulins, including haptoglobin, ceruloplasmin, high-density cholesterol (HDL), and alpha2 macroglobulin. Beta-globulins are also synthesized in the liver and include transferrin, plasminogen, low-density cholesterol (LDL), and complement proteins. The gamma-globulins, also called immunoglobulins, are produced by B cells in response to antigen stimulation and include IgA, IgD, IgE, IgG, and IgM immunoglobulins.
Serum protein electrophoresis is a widely used method of measuring albumin and each of the types of globulins. It is used to detect diseases such as multiple myeloma and other disorders in serum proteins, inflammatory conditions, autoimmune diseases, infections, and protein loss conditions. Serum protein electrophoresis is also used to investigate other abnormal laboratory results, such as when measuring total protein, albumin, and urine protein, low calcium levels, and low white and/or red blood cells. It can also be used to monitor the progression of certain diseases and their response to treatment.
Electrophoresis separates proteins based on their physical properties. The serum is placed in a special medium and an electric current is applied, causing the various proteins to be separated according to their electrical charge, molecular size, and shape. Albumin moves farther, followed by alpha-globulins, beta-globulins, and finally, gamma-globulins. These groups are then compared to different standards, features of specific diseases.
A homogeneous peak in the gamma-globulin region indicates monoclonal gammopathy. Monoclonal gammopathies are associated with malignant or potentially malignant conditions, including multiple myeloma, Waldenstrom's macroglobulinemia, leukemia, heavy chain disease, and amyloidosis. Polyclonal gammopathies can be the result of any reactive or inflammatory process. When a monoclonal gammopathy is found by electrophoresis of serum proteins, multiple myeloma must be excluded from other causes. This can be done by a method called immunofixation or immunoelectrophoresis. In immunoelectrophoresis, the specific proteins of interest can be determined after first being fixed in the gel with antibodies, and by removing all other proteins by washing, prior to staining. This enhances the effect of serum protein electrophoresis.
Possible Interpretations of Pathological Values
- Increased total protein: Macroglobulinemia, multiple myeloma, sarcoidosis
- Increased pre-albumin band intensity: Alcoholism
- Increased albumin band intensity: Acute pancreatitis. Medications: Aspirin, penicillins
- Increased intermediate space albumin-alpha1 globulin intensity: Alcoholism (chronic), women during adolescence and pregnancy
- Increased alpha-globulin band intensity: Acute phase response to inflammation (a1, a haptoglobin), acute rheumatic fever (a2), age (a2), albuminemia (a2), chronic glomerulonephritis (a2), cirrhosis (a1 elevated, a2 normal or only slightly elevated), diabetes mellitus (a2), familial idiopathic dysproteinemia, glomerular protein loss (a2 macroglobulin), liver damage, liver metastases (elevated a1 with normal a2), Hodgkin's disease (a1, a2), hypoalbuminemia, infancy (a2 zone is dominated by macroglobulin), acute infection, meningitis (a2), metastatic carcinoma (a1, a2), myocardial infarction, myxedema, nephrosis (a2), nephrotic syndrome (a2), osteomyelitis (a2), peptic ulcer (a1, a2), pneumonia (a2), nodular polyarteritis (a2), pregnancy (increased a1 with normal a2), enteropathy with protein loss (a1, a2), reumatoid arthritis (a2), sarcoidosis (a2), stress (a1, a2), systemic lupus erythematosus (a2), ulcerative colitis (a1, a2). Medications: Estrogens (increase a1 with little change to a2)
- Increased intermediate space a2-b1 globulin intensity: Hypercholesterolemia (type II), nephrotic syndrome, pregnancy
- Increased beta-globulin band intensity: Acute phase response (b2), analbuminemia, diabetes mellitus (poorly controlled), familial idiopathic dysproteinemia, glomerular protein loss, viral hepatitis, viral hepatitis macroglobulinemia, nephrotic syndrome, pregnancy (b1), rheumatoid arthritis, sarcoidosis. Medications: Estrogens, oral contraceptives (increase b1)
- Increased gamma-globulin band intensity: Acute viral hepatitis (sometimes), amyloidosis, albuminemia, advanced carcinoma, chronic hepatitis (oligoclonal zones), chronic hepatic disease (IgM), chronic lymphocytic leukemia (IgM paraprotein), chronic viral infections (occurrence of oligoclonal bands), cirrhosis (IgA), cryoglobulinemia, cystic fibrosis (IgG, IgA), Hashimoto's disease, liver disease, Hodgkin's disease, hypergammaglobulinemia, hypersensitivity reactions, severe infection, juvenile rheumatoid arthritis (IgG, IgA, IgM), Laennec cirrhosis, leukemia (myelogenous, monocyte), lymphosarcoma (IgM paraprotein), macroglobulinemia, multiple myeloma, IgG, respiratory tract infection, rheumatoid arthritis (IgA, IgM), sarcoidosis, scleroderma (sometimes), skin diseases (IgA), Sjögren's syndrome (IgG), systemic lupus erythematosus (IgM), Waldenstrom macroglobulinemia (IgM paraprotein)
- Decreased total protein: Analbuminemia, acute cholecystitis, chronic glomerulonephritis, Hodgkin's disease, hypertension (congestive heart failure), hypogammaglobulinemia, leukemia (myelogenous, monocytic), nephrosis, gastric ulcer, ulcerative colitis
- Decreased pre-albumin band intensity: Acute phase response (day 1), cirrhosis
- Decreased albumin band intensity: Acute rheumatic fever, analbuminemia, metastatic cancer, acute cholecystitis, diabetes mellitus, gastrointestinal protein loss (due to inflammatory or neoplastic disease), glomerular protein loss, chronic glomerulonephritis, liver disease, acute viral hepatitis, Hodgkin's disease, hyperthyroidism, hypertension (with congestive heart failure), Laennec cirrhosis, leukemia (lymphogenic, myelogenous, monocytic), lymphoma, macroglobulinemia, malnutrition, meningitis, multiple myeloma, nephrosis, nephrotic syndrome, osteomyelitis, peptic ulcer, pneumonia, nodular polyarteritis, enteropathy with protein loss, pyrexia, rheumatoid arthritis, sarcoidosis, stress, systemic lupus erythematosus, ulcerative colitis. Medications: corticosteroids
- Decreased intermediate space albumin-alpha1 globulin intensity: Cirrhosis, acute hepatitis, severe inflammation
- Decrease alpha-globulin band intensity: Acute viral hepatitis (a1, a2), congenital hypo-haptoglobulinemia (a2 haptoglobin), liver disease, intravascular hemolysis (hemolytic anemia, liver metastases, cirrhosis, splenomegaly cause decrease in a2 haptoglobin) malabsorption, pulmonary emphysema (a1), scleroderma, starvation, steatorrhea
- Decreased intermediate space a2-b1 globulin intensity: Diabetes mellitus, inflammation, pancreatitis
- Decreased beta-globulin band intensity: Autoimmune disease, metastatic cancer, liver disease (b1), immune complex disease (b2), leukemia (lymphocytic, monocytic, myelogenous), lymphoma, malabsorption, malnutrition (b1), nephrosis, scleroderma, starvation, steatorrhea, systemic lupus erythematosus, ulcerative colitis
- Decreased gamma-globulin band intensity: Acute viral hepatitis (sometimes), agammaglobulinemia, glomerular protein loss, hypogammaglobulinemia, lymphocytic leukemia, lymphoma, nephrosis, nephrotic syndrome, malabsorption, enteropathy with protein loss, scleroderma (sometimes), starvation, steatorrhea, ulcerative colitis
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.