What FLC ratio confirms biomarker of malignancy for myeloma?

Involved/uninvolved FLC ratio of 100 or above (with involved FLC 100 mg/L or above) is one of the three biomarkers of malignancy (SLiM criteria) that define symptomatic myeloma requiring treatment, even without CRAB criteria, per IMWG 2014 criteria.

Can the FLC ratio replace serum and urine protein electrophoresis?

No. FLC assay detects light chain production but misses intact immunoglobulin M-proteins detectable only by SPEP. For non-secretory and oligosecretory myeloma, FLC assay is the primary response assessment tool when SPEP is uninformative.

Free Light Chain Ratio Diagnostic Range

Interpret serum free light chain kappa/lambda ratio: normal range 0.26–1.65, values outside this range in the context of plasma cell disorders support MGUS, SMM, or MM diagnosis.

Use the full interactive calculator below, or

Related Calculators

Smoldering Myeloma

Medical Long-tail

MGUS Progression Risk

Medical Long-tail

Free Light Chain Ratio Diagnostic Range

Related Calculators

Frequently Asked Questions

What FLC ratio confirms biomarker of malignancy for myeloma?

Can the FLC ratio replace serum and urine protein electrophoresis?