Serum Protein Electrophoresis
February 15th, 2021
On this page:AlbuminAlpha-1 GlobulinsAlpha-2 GlobulinsBeta GlobulinsGamma GlobulinsSerum ParaproteinPolyclonal Gammopathy
Overview
Serum protein electrophoresis (EPG) separates serum proteins based on their electrical charge, producing a characteristic pattern.
Electrophoresis is a useful screening test for plasma cell neoplasms such as multiple myeloma and MGUS. If a plasma cell neoplasm is suspected then serum EPG should be ordered in conjunction with immunofixation electrophoresis (IFE) in order to quantify a paraprotein if present.
Elements of Protein Electrophoresis
- Albumin
- Alpha-1 - alpha 1-antitrypsin, thyroid-binding globulin
- Alpha-2 - caeruloplasmin, alpha 2-macroglobulin, haptoglobulin
- Beta-1 - transferrin
- Beta-2 - beta-lipoprotein
- Gamma - immunoglobulins
The elements of the complement pathway are present between the beta and gamma bands.
Albumin
The most abundant serum protein, produced by the liver. Important in maintaining oncotic pressure and transporting certain hydrophobic compounds.
Significance of Elevated Albumin
- Indicative of dehydration.
Causes of Hypoalbuminaemia
- Malnutrition
- Hepatic synthetic dysfunction
- Chronic infection
- Protein-losing enteropathies
- Nephrotic syndrome
- Severe burns
- Pregnancy
Alpha-1 Globulins
Include alpha-1 antitrypsin and thyroid-binding globulin.
Causes of Elevated Alpha-1 Globulins
- Acute inflammation
- Malignancy
- Pregnancy
Causes of Decreased Alpha-1 Globulins
- Alpha-1 antitrypsin deficiency
- Nephrotic syndrome
- Cirrhosis
Alpha-2 Globulins
Include caeruloplasmin, alpha 2-macroglobulin and haptoglobulin.
Causes of Elevated Alpha-2 Globulins
- Acute inflammation
- Adrenal insufficiency
- Corticosteroid administration
- Nephrotic syndrome
- Cirrhosis
Causes of Decreased Alpha-2 Globulins
- Malnutrition
- Haemolytic anaemia
- Protein-losing enteropathies
Beta Globulins
The beta-1 band is mostly transferrin, while the beta-2 band is mostly beta-lipoprotein.
Causes of Elevated Beta Globulins
- Iron deficiency anaemia
- Hypothyroidism
- Cushing's
- Biliary obstruction
- Polyarteritis nodosa
Causes of Decreased Beta Globulins
- Malnutrition
Gamma Globulins
Represents serum immunoglobulins IgG, IgM, IgA, IgD and IgE.
It is important to determine whether an elevated gamma globulin band is polyclonal (generalised elevation) or monoclonal (elevation of a small part of the band).
Serum Paraprotein
Causes of Monoclonal Gammopathy
Plasma Cell Neoplasms
- Monoclonal gammopathy of unclear significance (MGUS)
- Smouldering myeloma
- Multiple myeloma
- Solitary plasmacytoma
- AL amyloidosis
Others
- Waldenstrom's macroglobulinaemia
- Chronic lymphocytic leukaemia (CLL)
- Non-Hodgkin lymphoma
- Monoclonal (type II) cryoglobulinaemia
Polyclonal Gammopathy
Causes of Polyclonal Gammopathy
- Infection
- Inflammatory disease
- Malignancy
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