Liver Stiffness Measurement With FibroScan: Use the Right Probe in the Right Conditions!

FibroScan's M and XL probes give significantly different results, which could lead to misevaluation of liver fibrosis if the correct probe is not chosen. According to the manufacturer, the M probe should be used when the skin-liver capsule distance (SCD) is <25 mm, and the XL probe should be used when SCD is ≥25 mm. We aimed at validating this recommendation and defining the conditions of use for FibroScan probes in clinical practice.

Four hundred thirty-nine patients with biopsy-proven chronic liver disease were included. Of them, 382 had successful examinations with both M and XL probes. Advanced fibrosis was defined as Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) F ≥3 or Metavir F ≥2.

In a same patient, XL probe results were significantly lower than M probe results: 7.9 (5.6-11.7) vs 9.5 (6.7-14.6) kPa, respectively (P < 0.001). After matching for age, sex, liver fibrosis, and serum transaminases, M probe results in patients with SCD <25 mm and XL probe results in those with SCD ≥25 mm did not significantly differ: 8.8 (6.0-12.0) vs 9.1 (6.7-12.8) kPa, respectively (P = 0.175). Of note, 81.4% of patients with body mass index (BMI) <32 kg/m had SCD <25 mm, and 77.7% of patients with BMI ≥32 kg/m had SCD ≥25 mm. A practical algorithm using BMI first and then the FibroScan Automatic Probe Selection tool was proposed to help physicians accurately choose which probe to use in clinical practice.

There is no significant difference in results between M and XL probes when they are used in the right conditions. In clinical practice, the probe should be selected according to the BMI and the Automatic Probe Selection tool.