Cost-Effectiveness Analysis of Serum Free Light Chain Assay (Freelite®) for the Diagnosis of Monoclonal Gammopathy

Abstract

Current diagnosis protocols for monoclonal gammopathy (MG) rely on serum electrophoresis (SPEP) as the sole initial assessment for monoclonal protein, such as in Brazil, limited with respect to their sensitivity. Adding serum Free Light Chain (sFLC, Freelite®) determination results in a decreased number of false-negative results. We sought to assess the efficiency of sFLC for the diagnosis of MG in the Brazilian Public Health System (SUS) and Supplementary Healthcare System (SSS). Data from a published study on patients presenting with a suspicion of MG (n=652) was used to populate a decision tree model. The model was developed to distinguish which diagnosis protocol provides the highest value for each monetary unit invested. It were tested the standard protocol (SP) (SPEP as an aid in the diagnostic pathway), and two comparators, SP plus sFLC (PP1) and SP plus sFLC and Serum Immunofixation Electrophoresis (sIFE) (PP2). Results were interpreted as the amount of currency (BRL) spent for each incremental correct diagnosis of MG. Probabilistic simulation indicated an average ICER of BRL 1,192 and BRL 1,470 for PP1 and PP2, respectively in SUS. For SSS, the respective ICERs were BRL 3,620 and 4,193. Considering a threshold over BRL 1,500 (SUS) and BRL 4,000 (SSS), PP1 is the strategy more likely to be the cost-effective. The addition of sFLC assessment in the initial diagnostic work up of MG improves efficiency of financial resources allocated to MG diagnosis, with respect to the approaches taken in both SUS and SSS.