Serum free light chains benefit diagnosis of multiple myeloma in orthopaedic patients with normal serum total proteins, creatinine, calcium and hemoglobin

Abstract

Background: A substantial number of MM patients with bone destruction are initially admitted into Orthopedics due to bone pain. However, routine laboratory tests usually fail to identify these patients and delay optimal therapy. Therefore, there is a clear medical need in early diagnose MM on these patient population. Methods Ninety-four orthopaedic patients were enrolled from July 2019 to December 2021. Of them, 42 patients were diagnosed as MM during postoperative pathology, but exhibited normal serum total proteins, creatinine, calcium and hemoglobin before operation. The rest 52 orthopaedic patients were pathologically excluded from MM and recruited into control group. The immunofixation electrophoresis (IFE) assays were performed to detect sFLC levels of all the subjects for comprehensively analyzed. Results The sFLC κ/λ ratios in 37 out of 42 MM patients were outside the reference range (0.31 ~ 1.56). All 42 MM patients were divided into two groups based on sFLC, κ/λ ratio > 1 or κ/λ < 1 respectively. And there were no significant differences in levels of serum total proteins, creatinine, calcium and hemoglobin between these two groups and control group. Conclusions This study highlighted the clinical significance of sFLC detection in early diagnosis of MM in orthopedics patients with unexplained bone destruction, supporting appropriate treatment choices preoperatively.