Paraprotein typing

Specimen:

10 mL blood in plain tube.

Method:

IEP, IFE, IEF with immunofixation, immunosubtraction.

Reference Interval:

Qualitative test.

Application:

Characterisation of the light and heavy chains of monoclonal (M) bands (paraproteins) detected on electrophoresis.

Detection of small bands which may not be apparent on protein staining.

Interpretation:

The presence of an IgG, IgA or, less commonly, IgD paraprotein indicates Plasma cell myeloma or 'monoclonal gammopathy of uncertain significance'; some paraproteins are associated with AL amyloidosis and lymphoid neoplasms.

Monoclonal free light chains (Bence Jones protein) of significant amounts indicate myeloma.

Paraproteins and/or monoclonal free light chains may occasionally be found in primary amyloidosis.

An IgM paraprotein is characteristic of Waldenström's macroglobulinaemia but lower concentrations may be seen in other Lymphoproliferative disorders.

For quantitation of paraproteins, see Protein electrophoresis.

Reference:

Whicher J et al. Ann Clin Biochem 1987; 24: 119-132.