The diagnosis of NAFLD relies on histopathologic findings and includes a wide spectrum of lesions, including simple steatosis, steatohepatitis, and fibrosis, potentially leading to end-stage cirrhosis. Therefore, liver biopsy represents the gold standard to confirm NAFLD diagnosis and provide prognostic information, yet it is an invasive and costly procedure prone to either minor secondary effects, such as pain, or more severe complications, including a risk of death of 0.01%.13 Notably, there is high sampling variability and high intrapathologist and interpathologist inconsistency.14 Most importantly, facing the actual epidemic of diabetes and obesity15 and the subsequent number of patients at risk for liver alterations, biopsy cannot be considered a practical, efficient, and large-scale tool to identify those at risk for nonalcoholic steatohepatitis (NASH) and advanced fibrosis. To address this issue, less invasive tests have been developed and validated to largely screen NAFLD in at-risk populations (see review by Machado and Cortez-Pinto16). These methods are either biologic tests or physical techniques, such as transient elastography (FibroScan; Echosens). However, FibroScan has some limitations (failure or unreliability) in obese patients, as suggested by Castéra et al.17 Biologic tests prospectively validated by a predetermined scoring system equivalent to that of the METAVIR scoring system appear, then, to be the most appropriate tool in this population.18 The Fibromax patented algorithm19 developed by BioPredictive is a validated, noninvasive tool for NAFLD screening that uses the association of sex, age, weight, height, and numerous serum biomarkers. Fibromax includes SteatoTest (ST), NashTest (NT), and FibroTest (FT) for the noninvasive evaluation of steatosis, NASH, and liver fibrosis, respectively. The aims of this study were (1) to use noninvasive blood tests (ST, NT, and FT) to evaluate steatosis, NASH, and fibrosis in a large cohort of patients with OSA and a wide range of BMI values, including nonobese subjects, and (2) to assess endothelial function by peripheral arterial tone (PAT) as a marker of cardiovascular risk and evaluate its relationship with NAFLD in OSA.