Overview
Immunofixation is used with serum electrophoresis to determine the type and amount of monoclonal protein (M-protein, or paraprotein) present in a patient with a suspected plasma cell neoplasm, such as MGUS or multiple myeloma.
Immunofixation electrophoresis (IFE) is performed by separating plasma proteins by electrophoresis, followed by addition of specific antisera against each type of immunoglobulin.
Results of IFE
- Type of immunoglobulin present - IgG, IgM, IgA, IgD or IgE
- Type of light chain present - kappa or lambda
- Amount of paraprotein (g/L)
Standard IFE assesses the levels of immunoglobulins IgG, IgA and IgM, as these are the most commonly present in plasma cell neplasms; IgE and IgD may be tested if required. IFE also assesses for kappa or lambda free light chains.
There is normally no monoclonal protein (paraprotein) present in serum. If there is a paraprotein present at a level that is quantifiable, a measure of the amount of paraprotein will be provided. This is important in the diagnosis of MGUS (<30g/L) and smouldering myeloma (>30g/L), as well as for estimating risk of progression to multiple myeloma.
Diagnostic Criteria
Monoclonal Gammopathy of Uncertain Significance (MGUS)
- Serum monoclonal protein <30g/L
- Clonal bone marrow plasma cells <10%
- No evidence of end-organ damage (hypercalcaemia, renal dysfunction, anaemia, bony lesions) or amyloidosis
Smouldering Myeloma
- Serum paraprotein >30g/L or urinary paraprotein >500mg/24h and/or bone marrow plasma cells 10-60%
- No evidence of end-organ damage (hypercalcaemia, renal dysfunction, anaemia, bony lesions) or amyloidosis
Multiple Myeloma
- Clonal bone marrow plasma cells >10%
- AND evidence of end-organ damage (hypercalcaemia, renal dysfunction, anaemia, bony lesions)
- OR presence of biomarkers - >60% clonal plasma cells; serum free light chain ratio >100; more than one focal lesion >5mm on MRI
Next Page
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------