The objective of this study was to assess whether serum miRNA-122-5p, miRNA-486-5p, and miRNA-21-5p can serve as non-invasive diagnostic biomarkers for DKD by comparing their levels in T2DM patients with and without DKD against healthy controls, and by examining their correlations with inflammatory markers (IL-6, TNF-α, and hsCRP). The gene discussed is TNF; the disease is type 2 diabetes mellitus.