The study included 34 patients after knee arthroscopy, where the association between changes in inflammatory markers (∆CRP and ∆WBC) and occult blood loss (HBL) was investigated. Postoperatively, median CRP was 5.36 mg/L (IQR 2.80–12.20), mean WBC 9.25 ± 2.07 × 10^9/L, and median HBL 393.60 mL (IQR 273.42–672.97 mL). CRP and WBC levels increased significantly after surgery compared to preoperative values (p < 0.001). Neither univariate nor multivariate linear regression showed a significant association between ∆CRP, ∆WBC and HBL (p > 0.05), even after adjustment for covariates. Occult blood loss and a systemic inflammatory reaction are common after arthroscopy but are not independent of each other. The conclusion of the study states that postoperative inflammation and HBL represent different pathophysiological processes. Physicians should be aware that elevated inflammatory markers and postoperative fever do not indicate increased blood loss, and HBL is not a risk factor for infection.