Approximately 1 - 2% of patients with MM have biclonal gammopathies. When the light chain types differ (as occurs in around half of all biclonal cases), so that the patient has both κ and λ monoclonal sFLCs, κ/λ ratios can be normal 
. Since it is likely that both FLC concentrations would be elevated, and in different amounts, the clinician would usually be alerted to an abnormality (Figure 7.7
. The issue can be resolved by testing the sample using IFE and identifying two monoclonal bands of different FLC types. Renal function should also be determined to assess the degree of polyclonal elevation of sFLCs that might be attributed to reduced glomerular clearance.