Utilisation of sFLC assays - how well do we comply with guidelines?

Introduction: There is a paucity of data on the utilisation of the serum-free light chain (sFLC) and compliance with published guidelines. Methods: Serum-free light chain assays requested at our institute for the diagnosis, prognosis and monitoring of plasma cell dyscrasias from July 2008 to March 2010 were compared with the International Myeloma Working Group (IMWG) consensus guidelines. Results: In total, 1150 assays were performed (4.3 assays per patient, range 1-20). Eight hundred and forty-four (73%) of these were performed for multiple myeloma (MM), 188 (16%) for monoclonal gammopathy of undetermined significance, 72 (6%) for AL amyloidosis and 46 (4%) for smouldering myeloma. Of these, 49.6%, 22.9%, 1.4% and 69.6% of the monitoring assays were outside of IMWG recommendations, respectively. Of the 419 assays performed outside of guidelines for MM patients, 404 (96.4%) were due to monitoring of patients with a measurable M protein, while 24 (5.7%) were due to too frequent requesting (≤14 days) with 15 assays (3.6%) being noncompliant on both grounds. Conclusion: Utilisation of the sFLC assay shows reasonable adherence to guidelines within our centre. We propose to further optimise usage of the test with the help of administrative processes and education of clinicians.