When is an immunofixation test indicated?

Updated: Jul 29, 2019
  • Author: Anastasios Dimou, MD; Chief Editor: Eric B Staros, MD  more...
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Primary screening for plasma cell dyscrasias

No studies have addressed the role of serum or urine immunofixation in screening of the general population for multiple myeloma and related disorders. Therefore, such an approach cannot be currently recommended. [9]

Surveillance among patients with MGUS or smoldering (asymptomatic) multiple myeloma

Immunofixation of the urine and serum should be included in a battery of tests after 2-3 months following diagnosis of smoldering myeloma, then every 4-6 months for 1 year, and, finally, every 6-12 months if the results are stable. Surveillance for multiple myeloma in patients with MGUS and favorable prognostic factors (ie, low levels of monoclonal protein and IgG type) should include monitoring at 6 months and then every 2-3 years thereafter. For patients with MGUS and high risk for progression to multiple myeloma, surveillance should be performed at 6 months and then yearly thereafter. [13, 14]

Diagnosis of plasma cell dyscrasias [9]

Immunofixation is clearly indicated upon clinical or laboratory evidence of a plasma cell dyscrasia for the diagnosis of multiple myeloma, Waldenstrom macroglobulinemia, or amyloid light-chain (AL) amyloidosis. Typically, the monoclonal protein is discovered, and workup then ensues. These conditions should be promptly diagnosed and treated. In particular, when serum and urine protein electrophoresis results are negative, immunofixation is indicated as a more sensitive test if the clinical suspicion remains high. In addition, when protein electrophoresis assays are positive for a monoclonal protein, serum and urine immunofixation are indicated for the appropriate identification of the immunoglobulin and the corresponding light chain. However, most patients with a monoclonal protein will be finally diagnosed with MGUS rather than any of the malignant plasma cell dyscrasias for which treatment is recommended.

Follow-up of multiple myeloma, Waldenstrom macroglobulinemia, and AL amyloidosis

Immunofixation of urine and serum samples should be performed in all patients with multiple myeloma, Waldenstrom macroglobulinemia, and AL amyloidosis every 3 months after the completion of treatment in order to evaluate for response or to document a relapse. [15]

However, a study by Lahuerta et al indicated that, with the exception of persons with light-chain–only disease, urine immunofixation is not needed in combination with serum immunofixation to define complete response in multiple myeloma. Among 161 patients in whom both serum and urine demonstrated positive results for monoclonal protein and who were, posttreatment, negative for serum immunofixation, just 3 (1.9%) displayed positive urine immunofixation. [16]

Diagnosis of multiple sclerosis

Immunofixation in CSF for the detection of oligoclonal bands is indicated every time there is suspicion for multiple sclerosis. However, the presence of oligoclonal bands does not necessarily confirm the diagnosis, as other conditions can present with oligoclonal bands in the CSF.

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