title: Upper limits of normal for serum alanine aminotransferase levels in Chinese Han population.
abstract: OBJECTIVE
  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.
  
  
  BACKGROUND
  ChiCTR.org ChiCTR-OCS-11001173.
authors.affiliation: Department of Infection and Liver Diseases, Liver Research Center, the First Affiliated Hospital of Wenzhou Medical College, Wenzhou, China. blueman1320@163.com
authors.forename: Ming-Hua
authors.initials: MH
authors.lastname: Zheng
authors.forename: Ke-Qing
authors.initials: KQ
authors.lastname: Shi
authors.forename: Yu-Chen
authors.initials: YC
authors.lastname: Fan
authors.forename: Wen-Yue
authors.initials: WY
authors.lastname: Liu
authors.forename: Xian-Feng
authors.initials: XF
authors.lastname: Lin
authors.forename: Ling-Fei
authors.initials: LF
authors.lastname: Li
authors.forename: Yong-Ping
authors.initials: YP
authors.lastname: Chen
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood*; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005234:Fatty Liver / Q000097:blood* / Q000208:ethnology; D005260:Female; D006509:Hepatitis B / Q000097:blood* / Q000208:ethnology / Q000821:virology; D006515:Hepatitis B virus / Q000502:physiology; D006801:Humans; D008297:Male; D065626:Non-alcoholic Fatty Liver Disease; D011446:Prospective Studies; D012016:Reference Values; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012737:Sex Factors
chemical_list: D000410:Alanine Transaminase