At what BMI or waist-circumference threshold do you opt to move from Fibroscan to other NILDA for fibrosis assessment?  

The XL-validation study found a liver stiffness measurement (LSM) failure of 1% for the XL and 16% for the M probe, in patients with a BMI of 28 or above. In people with a BMI of 40 or above, the XL-probe failure was 5%, and the best predictor of failure was a skin-to-capsule distance (SCD) ≥25 m...