Upper limits of normal for serum alanine aminotransferase levels in Chinese Han population

PLoS One. 2012;7(9):e43736. doi: 10.1371/journal.pone.0043736. Epub 2012 Sep 4.


Background and objectives: Serum alanine aminotransferase (ALT) activity is the most common tool for the assessment of liver diseases. However, it is not clear whether the current normal ALT range really discriminate patients with or without liver diseases. The present study was to establish a new normal range of ALT and examine its ability to identify patients with hepatitis B or nonalcoholic fatty liver disease (NAFLD) in Chinese Han population.

Methods: 53037 adults were included in this study from January 1st 2008 to August 31st 2010. The 95th percentile of ALT in population with relative low risk factors for liver diseases was set as the new upper limits of normal ALT in gender-specific manner.

Results: The 95(th) percentile levels at low risk factors for liver diseases were achieved at 35 U/L for men and 23 U/L for women. The concordance statistics for detection were 0.873 (95%CI: 0.865-0.881) for HBV and 0.932 (95%CI: 0.927-0.937) for NAFLD in men while 0.857 (95%CI: 0.850-0.864) for HBV and 0.909 (95%CI: 0.903-0.915) for NAFLD in women. The median sensitivity of the current used ALT upper limit (40 U/L) was 6.6% for HBV and 29.7% for NAFLD and median specificity was 98.7% for men and 99.4% for women. Using our new-derived thresholds, the sensitivities ranged from 35.3% to 61.1% and the specificities were 94.8% for men and 94.6% for women.

Conclusions: Our results suggest that upper limits of ALT 35 U/L for men and 23 U/L for women in Chinese Han population. Re-consideration of normal limits of ALT should be recommended.

Trial registration: ChiCTR.org ChiCTR-OCS-11001173.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alanine Transaminase / blood*
  • China / epidemiology
  • Cross-Sectional Studies
  • Fatty Liver / blood*
  • Fatty Liver / ethnology
  • Female
  • Hepatitis B / blood*
  • Hepatitis B / ethnology
  • Hepatitis B / virology
  • Hepatitis B virus / physiology
  • Humans
  • Male
  • Non-alcoholic Fatty Liver Disease
  • Prospective Studies
  • Reference Values
  • Risk Factors
  • Sensitivity and Specificity
  • Sex Factors


  • Alanine Transaminase

Grant support

This work was supported by grants from National Science and Technology Major Project of China (2012ZX10002004), Scientific Research Foundation of Wenzhou, Zhejiang Province, China (H20090014, Y20090269), Health Bureau of Zhejiang Province (2010KYB070), Research Foundation of Education Bureau of Zhejiang Province (Y201009942) and Project of New Century 551 Talent Nurturing in Wenzhou. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.