AL: amyloid light chain; CRAB: hypercalcemia, renal insufficiency, anemia, bone lesions; CT: computed tomography; eGFR: estimated glomerular filtration rate; FISH: fluorescence in situ hybridization; FLC: free light chain; IgA: immunoglobulin A; IgD: immunoglobulin D; IgG: immunoglobulin G; IgM: immunoglobulin M; LDH: lactate dehydrogenase; M: monoclonal; MGUS: monoclonal gammopathy of undetermined significance; MM: multiple myeloma; MRI: magnetic resonance imaging; PET: positron emission tomography; SLiM: ≥60% clonal plasma cells in the bone marrow; involved/uninvolved FLC ratio of 100 or more (provided involved FLC level is at least 100 mg/L); MRI with more than 1 focal lesion (involving bone or bone marrow); SPEP: serum protein electrophoresis; WM: Waldenström macroglobulinemia.
* Patients with solitary plasmacytoma, nonsecretory MM, and rare cases of AL amyloidosis may not have detectable M protein or abnormal serum FLC assay.
¶ The iStopMM risk model is available at https://istopmm.org/riskmodel/.
Δ Imaging should be performed using whole-body low-dose CT, whole-body PET/CT, whole-body MRI, or MRI of the spine and pelvis (depending upon availability and institutional preference). Biopsy of the bone lesion should be performed if a solitary lesion is detected or if the cause of the lesion is unclear. Bone imaging may be omitted for patients with IgM M protein and no clinical concern for bone lesions or myeloma.
◊ When interpreting the FLC assay in clinical practice, clinicians should refer to the normal reference range specified by the laboratory reporting the result. Reference ranges differ between assays from different manufacturers and are dependent upon the instrument used for measurement. Reference ranges may also be adjusted for the patient's estimated glomerular filtration rate[1]; for the serum FLC assay developed by The Binding Site:Do you want to add Medilib to your home screen?