Comparision of the diagnostic sensitivity of biochemical tests in the screening of monoclonal gammopathy

Abstract

: Monoclonal gammopathy include several clinical variants ranging from asymptomatic MGUS, asymptomatic smouldering myeloma, multiple myeloma to aggressive plasma cell leukemia. The characteristic property of myeloma cells is the production and secretion of M protein. Due to its diverse structure, no single test can identify M protein accurately in all patients. A simple, non-invasive combination of tests is necessary for the screening of monoclonal gammopathy. The present study aims to assess the diagnostic sensitivity of the biochemical tests used in the screening of monoclonal gammopathy.: This study was conducted retrospectively of the newly diagnosed cases of monoclonal gammopathy screened with SPE and ISUB/IT using sebia capillary electrophoresis and serum free light chain ratio using immunoturbidimetry method.: Out of the 142 patients included in the study, 120 had M band in SPE, 125 had monoclonal gammopathy by ISUB/IT and 121 patients had abnormal sFLCR. The diagnostic sensitivity obtained was 84.5% 88% and 85.2% for SPE, ISUB/IT and sFLCR respectively. Addition of sFLCR to SPE and ISUB/IT could identify 20 patients who had no abnormality in either of these tests. The combined sensitivity of SPE and ISUB/IT was 88%, while that of SPE and sFLCR and a combination of all the three tests was 98.6%. The simple, non-invasive, cost-effective screening panel of SPE plus sFLC ratio could be used as the initial screening method for patients with suspected monoclonal gammopathy with increased reliability.