Reference Values
The ledger. Kappa:lambda ratios, M-protein thresholds, bone marrow plasma cell percentages, and CRAB criteria, all with units, ranges, and sources.
Reference-standard: 1/16 or less, or 16 or more. Highest diagnostic accuracy: 1/7 or less, or 9 or more. Two cutoffs from one paper; both entered.
Primary source establishing serum FLC ratio range 0.26 to 1.65 (extended from 95% CI 0.30 to 1.20 to include all 282 reference sera). The contradiction between these two numbers from one paper is entered.
ARUP assay reference intervals: kappa 3.30 to 19.40 mg/L; lambda 5.71 to 26.30 mg/L; ratio 0.26 to 1.65. Immunoturbidimetry.
Reference for plasma cell ultrastructure on H&E: clock-face nucleus, perinuclear hof, basophilic cytoplasm, N:C ratio, CD138 marker. Cited for morphology and methods sections.
IMWG measurable disease threshold: serum M-protein 1.0 g/dL or more; SPEP minimum reliable detection: 0.5 g/dL. Secondary source; primary IMWG citation flagged for next pass.
Reference intervals differ by assay platform; argues against direct cross-platform comparison of FLC ratios. Relevant tension in the reference-values registry.
In 701 NDMM patients, sFLC ratio normalization during the first four induction cycles provided independent prognostic information detectable earlier than MRD assessment.
Argues that the sFLC ratio 100 or more threshold as a standalone myeloma-defining event is a poor predictor of progression risk and calls for revision of IMWG diagnostic criteria.
Ten-year review in Blood evaluating whether the sFLC 100 or more criterion remains valid as a myeloma-defining event given heterogeneous real-world outcomes.
iStopMM population-based cohort provides revised serum free light chain reference intervals; proposes updated thresholds for light chain MGUS diagnosis.