Studies have reported the value of summated κ and λ sFLC concentrations in a number of conditions ranging from CLL (Chapter 33) and cardiovascular disease (Section 35.3) to HIV infection (Section 35.6). Faint and colleagues [684] recently described the development of a new turbidimetric sFLC immunoassay that measures both κ and λ sFLCs simultaneously, producing a measurement of summated FLCs in a single assay (Combylite, cFLC). This should allow easier testing of sFLCs in a variety of inflammatory conditions.