The combination of serum IL-34, type IV collagen 7s, and ages, which are independent factors of liver fibrosis [IL-34-based fibrosis score (IL-34-FS) = 0.0387 × IL-34 (pg/mL) + 0.3623 × type IV collagen 7s (ng/mL) + 0.0184 × age (year) - 1.1850] was a practical tool for predicting the stages of fibrosis in NAFLD patients. This evidence concerns the gene IL34 and fibrosis.