This study examines how BMI, shear wave speed (SWS), and skin-to-liver capsule distance affect the accuracy of liver ultrasound-derived fat fraction (UDFF). Using MRI Proton Density Fat Fraction (PDFF) as the gold standard, data from 196 patients show an intraclass correlation coefficient (ICC) of 0.79 between UDFF and PDFF. Notably, stronger correlations are observed in subjects with a BMI less than 30 Kg/m², SWS below 1.7 m/s, and skin-to-capsule distance under 2.3 cm. These confounding factors are critical for precise UDFF interpretation in clinical settings.