Immunofixation, Isatuximab-Specific, Serum

CPT 82784(x3); 86334
  • Electrophoresis, Serum, IFE
  • HYDRASHIFT 2/4 isatuximab
  • IEP, Serum
  • IFE, Serum
  • Immunoelectrophoresis, Serum
  • Immunofixation
  • Serum IEP
  • Serum Immunoelectrophoresis;
  • Serum Immunofixation

Test Details

Turnaround Time

4 - 8 days


Detect and identify monoclonal immunoglobulin gammopathies in the presence of therapeutic monoclonal antibody (mAbs) drug treatment with isatuximab (SARCLISA®), a human IgG1 kappa mAb, which migrates in the electrophoretic gamma globulin zone of the electrophoresis gel. In this laboratory procedure, the isatuximab in vitro interference is removed using an anti-isatuximab antibody reagent. This procedure will characterize the specific light and heavy chain components of a monoclonal protein without isatuximab interference.

Special Instructions

State patient's age and clinical diagnosis on the test request form.


Electrophoresis followed by immunodiffusion against mono-specific antisera to immunoglobulin and individual heavy and light chains (IFE); turbidimetric quantitation of IgA, IgG, IgM.

The HYDRASHIFT 2/4 isatuximab gel shift assay uses an anti-isatuximab antibody to allow for the migration of isatuximab/anti-Isatuximab complexes away from the gamma globulin zone on IFE, toward the alpha-1-globulin fraction, thus removing IgG kappa interference in the gamma globulin zone caused by isatuximab in the patient's serum.

Additional Information

SARCLISA® (isatuximab) is a human monoclonal IgG Kappa antibody targeting CD38 that has been shown to provide clinical benefit as monotherapy in heavily pre-treated multiple myeloma patients and when combined with standard of care regimens for the treatment of MM in patients with the earlier disease.

The HYDRASHIFT 2/4 isatuximab reagent allows the laboratory to distinguish isatuximab interference from endogenous M protein1 on Hydragel IF assay.

A negative immunofixation result with HYDRASHIFT 2/4 isatuximab may suggest a complete response (CR) or stringent complete response (sCR) to therapy along with other clinical assessment for patients receiving isatuximab.2

Specimen Requirements

Information on collection, storage, and volume




2 mL

Minimum Volume

1 mL


Red-top tube or gel-barrier tube

Storage Instructions

Room temperature

Causes for Rejection

Plasma sample


Separate serum from red cells.