Yield of diagnostic tests in obese children with an elevated alanine aminotransferase

Acta Paediatr. 2015 Dec;104(12):e557-63. doi: 10.1111/apa.13176.


Aim: Nonalcoholic fatty liver disease (NAFLD) is associated with obesity and affects roughly 10% of children. However, NAFLD is often diagnosed by exclusion - that is, obese children with an elevated alanine aminotransferase (ALT) are screened for other liver diseases in the absence of a biopsy. This testing is nonstandardized, and professional society recommendations differ. This study examines the yield of testing for disorders other than NAFLD in this patient population.

Methods: A retrospective study was performed in 120 obese, asymptomatic, noncholestatic children with an ALT ≥40 U/L and additional diagnostic testing.

Results: No patients were found to have Wilson's, hepatitis A, hepatitis B, hepatitis C, cytomegalovirus, alpha-1 antitrypsin deficiency, autoimmune hepatitis, celiac disease or Epstein-Barr virus. Only one patient (1/120) was identified with definite disease other than NAFLD, which was muscular dystrophy. The positive predictive value of a screening test was 5%, and the specificity was 97%. Of 70 children with an abdominal ultrasound, no significant abnormalities were identified.

Conclusion: Extensive testing in asymptomatic, noncholestatic, obese children with an elevated ALT may be of limited diagnostic value and false-positive tests are likely. Large, prospective studies are needed to help focus the work up in this patient population.

Keywords: Alanine Transaminase; Mass Screening; Nonalcoholic Fatty Liver Disease; Obesity.

MeSH terms

  • Adolescent
  • Alanine Transaminase / blood*
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Liver Diseases / blood
  • Liver Diseases / diagnosis*
  • Liver Diseases / etiology
  • Male
  • Obesity / blood
  • Obesity / complications*
  • Retrospective Studies


  • Alanine Transaminase