Guidelines for Free Light Chain Measurements

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Guidelines for Free Light Chain Measurements
5th International Symposium on Clinical
Applications of
Serum-Free Light Chain Analysis
Brian G.M. Durie, M.D. On behalf of the
International Myeloma Working Group
Friday, Sept. 19, 2008
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Are these sheep up for contract renewal?
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Overview Summary of Free Light Chain Test

• Serum Test (not urine)
• More sensitive than SPE or IFE
• Used for
• Diagnosis
• Prognosis
• Response Assessment
• Disease Monitoring
• Practical caveats important
• Cost effective and available

Dispenzieri et al. Leukemia, In Press 2008
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Diagnosis
Question of Monoclonal Plasma Cell Disorder
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Is 24hr Urine UPEP/IFE Required?
If Urine IFE Positive

• sFLC Ratio Abnormal 86
• sIFE Abnormal 93.5
• One or Both Abnormal 99.5

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Prognosis

• MGUS
• Solitary Plasmacytoma
• Smoldering Myeloma
• Active Myeloma
• Amyloidosis

• Be Aware of Other Testing
• Solitary ? - PET-CT Helpful
• Amyloid Cardiac Troponin

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Risk of Progression in MGUS

• IgG lt 1.5 gm/dl M-spike

Low Risk

• Normal Freelite Ratio

High Risk

• Not IgG
• Spike 1.5gm/dl
• Abnormal Ratio

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Solitary Plasmacytoma and Smoldering Myeloma
Mayo data sets
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TT3 Inferior Survival with Top-Tertile SFLC
Level at Baseline
Impact of Serum Free Light Chain (SFLC)
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Response Assessment

• Oligo secretory YES
• Light Chain Only Maybe
• Intact Immunoglobulin Maybe
• Amyloidosis YES

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Current Recommendations for Response Assessment

• Routine Use
• Oligo Secretory
• Amyloidosis
• Also all patients to assess
• Stringent CR (sCR)

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6 Mos. Earlier Indication of Relapse Than IFE
, ( mg/L)
6-mo Earlier Indication of Relapse
Mosbauer et al. Haematologica 200792275-276
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Caveats and Cautions

• Always double-check units (mg/l mg/dl)
• Consider
• Antigen Excess (Aberrant Low)
• Polymerization (Aberrant High)
• Lot-Lot Variation
• Non-Linear Dilution
• Impact of Renal Dysfunction
• Impact of Ongoing Treatment

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Value of sFLC

• Diverse Uses
• Readily Available
• Cheap
• Even doctors can learn how to interpret results!

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