Serum Protein Electrophoresis
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).
Polyclonal Gammopathy
![Gamma Globulins]()
Causes of Polyclonal Gammopathy
- Infection
- Inflammatory disease
- Malignancy
Monoclonal Gammopathy
![Gamma Globulins]()
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
Hypogammaglobulinaemia
Causes of Hypogammaglobulinaemia
Inherited
- Primary hypogammaglobulinaemia
Reduced Production
- Malnutrition
- Malignancy - especially CLL, lymphoma, multiple myeloma
- Inflammatory disease - SLE, RA
- Viruses - HIV, EBV, CMV, rubella
Increased Consumption
- Sepsis
- Severe burns
- Protein-losing enteropathy
- Nephrotic syndrome
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