We observed the diagnostic power of cathepsin B to predict liver fibrosis as a function of the METAVIR score: Control vs. F2 + F3 + F4, AUROC = 0.992 ± 0.006 (95%CI = 0.98–1.00; p < 0.0001), Control + F2 vs. F3 + F4 AUROC = 0.98 ± 0.01 (95%CI = 0.96–1.01; p < 0.0001) and Control + F2 + F3 vs. cirrothic F4 AUROC = 0.95 ± 0.02 (95%CI = 0.91–0.99; p < 0.0001). Here, CTSB is linked to Hepatic fibrosis.