[Correlation between Serum Free Light Chain and Blood Routine Parameters in Patients with Multiple Myeloma]

To investigate the correlation between serum free light chain (sFLC) and blood routine parameters in patients with multiple myeloma (MM).

347 patients with multiple myeloma diagnosed in Sichuan people's Hospital from April 2019 to July 2021 were selected. sFLC, serum total light chain (sTLC), peripheral blood routine, coagulation and biochemical parameters were analyzed retrospectively. The correlation analysis between sFLC and blood routine parameters were calculated by Pearson or Spearman correlation coefficients. Multiple stepwise linear regression was used to screen the combined blood routine parameters related to sFLC. The efficacy of the selected blood routine parameters eflecting sFLC level was evaluated, the Kruskal Wallis test of independent samples was used for inter group comparison, and the receiver operating characteristic (ROC) curve was drawn at the same time.

In MM patients, sFLC was positively related with sTLCκ, sTLCλ, sTLCκ/λ, Cr, Urea, Cr and Cys_C significantly, while negatively correlated with eGFR markedly (｜r｜≥0.3). Multivariate stepwise linear regression showed that the influence factors of sFLCκ were Cr and sTLCκ (P=0.000, P=0.003), the influence factors of sFLCλ were eGFR and sTLCλ(P=0.000, P=0.000), the sFLCκ/λ influence factor was sTLCκ/λ (P=0.032). Kruskal Wallis test of independent samples showed that Cr and sTLCκ, eGFR and sTLCλ, TLCκ/λ were good or better parameters to reflect the level of sFLCκ, sFLCλ and sFLCκ/λ in MM patients(P＜0.05), respectively. ROC curve analysis shows that Cr, sTLCκ, eGFR, sTLCλ and sTLCκ/λ had the ability to judge the abnormality of sFLC in MM patients (AUC=0.684-0.875, P＜0.05).

In MM patients, sTLCκ and sTLCλ with renal function parameters could evaluate sFLCκ or sFLCλ level respectively, while sFLC κ/λ was estimated by sTLCκ/λ.