Diagnosis

For a positive diagnosis of NAFLD to be made, there should be

  1. Hepatic steatosis by imaging or histology
  2. No significant alcohol consumption
  3. No competing aetiologies for hepatic steatosis, such as hepatitis C, steatogenic drugs, parenteral nutrition, Wilson’s disease and severe malnutrition
  4. No coexisting causes of chronic liver disease, such as hemochromatosis, autoimmune liver disease, chronic viral hepatitis, alpha-1 antitrypsin deficiency, Wilson’s disease and drug-induced liver injury

Once, a diagnosis of NAFLD has been established, patients should be assessed for NASH or fibrosis. While a liver biopsy remains the gold standard to differentiate NAFL from NASH and rule out other chronic liver diseases, elastography and scoring systems based on clinical features and routine biochemical testing can be used to assess fibrosis in patients with NAFLD and thus avoid invasive interventions that can be costly, risky, and potentially painful. Current guidelines thus recommend that patients suspected of having NASH and/or steatohepatitis should undergo liver biopsy, as non-invasive techniques are expensive have not yet been validated. Biomarkers, fibrosis scores and elastography are recommended as acceptable non-invasive procedures for the identification of cases at low risk of advanced fibrosis/cirrhosis. New metabolomic biomarkers and genetic testing are currently under investigation.

Simplified algorithm for the diagnosis of NASH

References

  1. Chalasani N, Younossi Z, Lavine JE, et al. The diagnosis and management of nonalcoholic fatty liver disease: Practice guidance from the American Association for the Study of Liver Diseases. Hepatology. 2018;67:328-57
  2. Byrne CD, Patel J, Scorletti E, Targher G. Tests for diagnosing and monitoring non-alcoholic fatty liver disease in adults. BMJ. 2018;362:k2734
  3. Imajo K, Kessoku T, Honda Y, et al. Magnetic Resonance Imaging More Accurately Classifies Steatosis and Fibrosis in Patients With Nonalcoholic Fatty Liver Disease Than Transient Elastography. Gastroenterology. 2016;150:626-37 e7
  4. Toplak H, Stauber R, Sourij H. EASL-EASD-EASO Clinical Practice Guidelines for the management of non-alcoholic fatty liver disease: guidelines, clinical reality and health economic aspects. Diabetologia. 2016;59:1148-9
  5. Bril F, Millan L, Kalavalapalli S, et al. Use of a metabolomic approach to non-invasively diagnose non-alcoholic fatty liver disease in patients with type 2 diabetes mellitus. Diabetes Obes Metab. 2018;20:1702-09