British guidelines on the diagnosis and management of MM published in 2011  have been updated in 2013  and 2014 . These guidelines include the following uses of sFLC and Hevylite measurements:
Investigation and diagnosis
The guidelines recommend that the IMWG diagnostic criteria are used (Section 25.2). Assessment of sFLCs is recommended as part of the diagnostic work-up of patients where there is a strong suspicion of myeloma but in whom routine SPE is negative. sFLC analysis is particularly useful in the initial investigation of patients with LCMM, NSMM and oligosecretory disease, and in cases where urine has not been supplied to the laboratory (Chapters 23 and 24).
Prognostic factors in symptomatic myeloma
The guidelines recommend that the International Staging System (based on serum albumin and β2-microglobulin) be used, and that fluorescent in situ hybridisation (FISH) studies are used for all patients at diagnosis. The guidelines recognise that newer techniques for prognostic assessment should continue to be utilised in the context of clinical trials to evaluate future incorporation into routine clinical practice, and highlight that baseline sFLC concentrations and the immunoglobulin heavy/light chain (Hevylite®) ratio, both at diagnosis and following treatment, may provide useful prognostic information (Chapter 20).
Measuring response to therapy
The guidelines recommend that response to therapy is defined according to the IMWG uniform response criteria (Section 25.3.5) but that the stringent complete response (sCR) category is necessary only in the context of a clinical trial. sFLC assays should be used to routinely assess response in all patients with LCMM, NSMM and oligosecretory disease: in routine clinical practice there is a clear rationale for utilising the sFLC assay to assess response in light chain only disease, irrespective of the extent of light chain excretion in the urine. sFLC analysis should also be performed as part of the initial management of patients with renal failure.
Monitoring patients with SMM should include regular clinical assessment and monoclonal protein measurement, including sFLC analysis when indicated.