Clinical Significance of Serum Free Light Chain Test in the First Onset of Multiple Myeloma

Clinical significance of serum free light chain (sFLC) test in the diagnosis, efficacy evaluation, prognosis judgment of first onset of multiple myeloma (MM).

Medical records of 39 cases of first-onset MM were gathered in our hospital from 1/2010 to 2/2012, including 25 male and 14 female patients with the median age being 63 years old. sFLC-kappa and sFLC-lambda were determined by immune turbidimetric assay, sFLC-kappa/lambda were calculated and the results were compared with that of immunofixation electrophoresis (IFE) as well as serum protein electrophoresis (SPE) for sensitivity assessment. All patients were treated with chemotherapy followed by sFLC detection and efficacy assessment. Patients with a sFLC results higher than median were marked as high-sFLC, the rest were marked as low-sFLC, and survival analysis were made comparing the two groups.

Of the 39 first-onset MM patients, 38 were detected as sFLC- kappa/lambda positive, that's a sensitivity of 97. 4%, higher than IFE (79. 5%), SPE (53. 8%), and uPE (38. 5%). As condition improves after treatment, sFLC gradually decline and sFLC- kappa/lambda level falls back to normal. Evaluation of efficacy by sFLC results has an accuracy of 77. 27%, significantly higher than that of corresponding M protein test£̈ P=0. 009£©. Follow-up survival analysis showed that the OS time and TTP time of low-sFLC group are significantly higher than those of high-sFLC group (P=0. 037, 0. 009 respectively).

sFLC detection is a highly sensitive quantitative method, can help the diagnosis of MM, gives a quicker assessment of treatment efficacy, and can predict disease recurrence. When it's the first onset, sFLC level can also roughly forecast the prognosis.

No relevant conflicts of interest to declare.