EXENT® GAM Assay
Overview
What is the EXENT GAM Assay?
The EXENT GAM Assay is a sensitive and specific immunoassay that identifies and quantifies M-proteins based on their unique molecular mass. Sample preparation uses paramagnetic beads specific to human IgG, IgA, IgM, total Kappa and total Lambda to isolate immunoglobulins from patient serum. The isolated immunoglobulins are analysed by MALDI-ToF mass spectrometry to specifically measure the monoclonal protein component. The assay is used in conjunction with the Binding Site Optilite® IgG, IgA and IgM assays to enable quantification of the identified monoclonal proteins.
A new paradigm for the detection & quantification of M-proteins
Monoclonal protein detection using mass spectrometry
Each plasma cell produces a unique immunoglobulin
Immunoglobulin molecules consist of two identical heavy chains and two identical light chains (Kappa or Lambda)
When immunoglobulins have their inter-chain disulphide bonds reduced, they are dissociated into their constituent heavy and light chains. The reduced light chains from the intact immunoglobulins are ideally suited to analysis by MALDI-ToF mass spectrometry due to their low molecular weight
The resulting mass spectra reflects the plot of mass vs intensity of the isolated and reduced immunoglobulins
| (A) When immunoglobulins are isolated from the serum of a healthy individual, by specific immunopurification, the resulting MALDI-ToF mass spectrometry resolves three normally distributed peaks that are representative of the polyclonal Lambda, Kappa and heavy Kappa free light chains derived from the intact immunoglobulins.1 |
| (B) In a patient with a monoclonal gammopathy, the presence of a sharp peak within the polyclonal background is indicative of the presence of a monoclonal immunoglobulin. The molecular weight of the identified peak can be used to specifically track the monoclonal protein and the peak area ratio of the monoclonal to polyclonal can be combined with the Optilite IgG, IgA or IgM assay to derive a quantification. |
When a monoclonal protein is identified, a simple calculation is applied to provide quantification based on the total immunoglobulin value derived from the Optilite IgG, IgA or IgM assay.
How can the EXENT GAM Assay be used?
Can aid the diagnosis of monoclonal gammopathies i.e:
- MGUS (Monoclonal Gammopathy of Undetermined Significance)
- SMM (Smoldering Multiple Myeloma)
- MM (Multiple Myeloma)
- Waldenström’s Macroglobulinemia
- AL Amyloidosis
Can aid the monitoring of:
- MM (Multiple Myeloma)
- Waldenström’s Macroglobulinemia
Baseline to monitoring
Explore the step-by-step EXENT GAM assay guide:
Request with baseline serum sample
EXENT GAM Assay
The baseline serum sample is critical to identify a patient’s M-protein along with its unique molecular mass. This can be used to accurately monitor the specific M-protein at subsequent timepoints during treatment.
Measure with baseline serum sample
Measure follow-up samples using the EXENT GAM Assay
Once the patient's M-protein has been identified, it can be reported. Report this clone but do not report other oligoclonal (transient) peaks as the clinical significance of peaks <0.2 g/L in a diagnostic setting is not well understood. Record the M-protein for future analysis and tracking.
Review Results
Report relevant/persistent clones(s) with EXENT GAM Assay
Review and record the patient's M-protein for future analysis and tracking. Other oligoclonal (transient) peaks may be included as a comment as the clinical significant of oligoclonal peaks is not well understood.
Release
- Report final results to the request clinician or laboratory
- Save patient results in database for future analysis
Related content
Product availability is subject to country specific regulatory requirements. Contact your local representative for availability in your country.
This product is not commercially available in the USA or China. Future commercial availability cannot be guaranteed.
EXENT and Optilite are registered trademarks of The Binding Site Group Limited (Birmingham, UK) in certain countries.
The EXENT® System combines EXENT® Analyser with Immunoglobulin Isotypes (GAM) for the EXENT® Analyser.
EXENT GAM Assay refers to Immunoglobulin Isotypes (GAM) for the EXENT® Analyser.
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References
- Barnidge DR, et al. Subset of kappa and lambda germline sequences result in light chains with a higher molecular mass phenotype. J Proteome Res 2015; 14:5283-90