Free light chains are produced by plasma cells; these are the cells responsible for the production of antibodies, also called immunoglobulins.
An antibody is made up of heavy chains and light chains. The heavy and light chains are bound together to form an intact immunoglobulin.
These two proteins are produced independently and assembled within the plasma cells.
The light chains are produced in excess and therefore they can be found also as free proteins in the serum. This is why they are called serum free light chains.
Free light chains are an excellent biomarker to evaluate the uncontrolled growth of plasma cells, typical of blood cancers such as Multiple Myeloma, as they can often be found at concentrations proportional to the tumour burden.
What is this test?
Freelite assays are based on polyclonal antisera, targeting kappa and lambda free light chains respectively.
Freelite assays are highly sensitive and specific. The analytical sensitivity and specificity of Freelite assays is achieved by the use of latex particles coated with affinity purified polyclonal antibodies.
Freelite assays can be used in serum, EDTA and lithium heparin plasma, urine, and cerebrospinal fluid (CSF) using the Binding Site Optilite® automated Analyser.
In serum, plasma, and urine, the assay can aid in the diagnosis and monitoring of monoclonal gammopathies, such as:
In CSF, the Freelite Mx assay aids in the characterisation of intrathecal immunoglobulin synthesis.
What is this test?
Freelite assays were the first commercially available automated FLC immunoassays, released worldwide in 2001.
Freelite assays are used in the largest multiple myeloma centers worldwide.
Free light chain values in national and international guidelines are based on results obtained using Freelite assays.
Freelite assays use polyclonal antisera to detect the widest range of free light chains. This is important due to the large variety of free light chains that can be produced by plasma cells.
Many studies have proven that free light chain assays are not interchangeable1,2,3, so changing assays will require patient sample re-baselining and continuity of multiple myeloma monitoring is crucial.
Decisions based on clinically proven assays minimize risk for patient management.
Freelite assays are the most widely used free light chain tests, providing the confidence and performance you need for optimal patient management
Freelite for Guideline Compliant Testing
Freelite assays detect low levels of light chains, not quantifiable by conventional methods such as SPE.11 They are able to detect free light chains even when serum or urine immunofixation may not.
Freelite assays are able to measure FLC above, within and below the reference interval. This means they can provide information on both the involved FLC and the uninvolved FLC.
Freelite assays can be ~10-fold higher sensitivity compared to uIFE.12
Freelite assays on the Optilite® Analyser provide the optimal laboratory solution for free light chain testing
|Optilite is a registered trademark of The Binding Site Group Ltd (Birmingham, UK) in certain countries.|
Together, ‘Freelite’ and ’Hevylite’ assays provide more information when monitoring Multiple Myeloma, including Non secretory, Oligo-secretory MM (NSMM), Light Chain Multiple Myeloma (LCMM), AL Amyloidosis
|Quantifies κ and λ free light chains in serum||Quantifies individual heavy + light chain (HLC) isotypes in serum.|
|Discordant κ/λ FLC ratio is a sensitive marker of light chain clonality||Molecules are measured in pairs, e.g., IgGκ/ IgGλ, to produce HLC ratios, which can identify plasma cell clonality|
|sFLC assays + SPE = diagnosis of Multiple Myeloma||HLC assays allows quantification for difficult to measure M proteins|
|Detects light chain escape at relapse||When uninvolved HLC concentration is below the reference range this may indicate immunosuppression|
|AL: Amyloid light chain; CR: Complete response; LCMM: Light chain mltiple myeloma; HLC: Heavy light chain; MGUS: Monoclonal gammopathy of unknown significance; MM: Multiple Myeloma; NSMM: Nonsecretory multiple myeloma; sCR: stringent complete response; SPE: Serum Protein Electrophoresis; sFLC: serum-free light chain assay|
|*Only IgG and IgA Hevylite assays are indicated for monitoring only in previously diagnosed patients|