How many more MM patients will be detected if I perform sFLC assays together with SPE and IFE?
FLC serum assays are more sensitive for FLC detection than both SPE and IFE so approximately 5% extra patients with low concentration monoclonal FLCs will be detected. Some of these patients will have LCMM, NSMM or AL amyloidosis. Many of these patients also have FLCs in the urine but some do not. If monoclonal FLCs are detected in the serum then there is little value in performing additional urine tests. However, there are rare patients that have normal sFLC concentrations but have detectable FLCs in concentrated urine by IFE. These include patients with AL amyloidosis but not patients with LCMM.
