title: Updated definitions of healthy ranges for serum alanine aminotransferase levels.
abstract: BACKGROUND
  Serum alanine aminotransferase (ALT) activity, the variable most commonly measured to assess hepatic disease, fails to identify many patients with hepatic injury. Current standards for "normal" ALT level were defined by using populations that included persons with subclinical liver disease.
  
  
  OBJECTIVE
  To update definitions of healthy ranges for serum ALT level.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  A university hospital in Milan, Italy.
  
  
  METHODS
  6835 persons who were first-time blood donors from 1995 through 1999, were negative for anti-hepatitis C virus (HCV), and had no contraindications to donation and 209 persons who attempted to donate blood from 1990 through 1999 but were found to have anti-HCV antibodies. Of the latter group, 131 had HCV viremia.
  
  
  METHODS
  Univariate and multivariate analyses examined associations between clinical and laboratory factors and ALT levels. Healthy ranges for ALT were computed from the population at lowest risk for liver disease. Sensitivity and specificity of healthy ALT ranges were evaluated in the donors with HCV antibodies, of whom 133 had liver biopsy.
  
  
  RESULTS
  Serum ALT activity was independently related to body mass index and to laboratory indicators of abnormal lipid or carbohydrate metabolism. Updated upper limits (for men, 500 nkat/L [30 U/L]; for women, 317 nkat/L [19 U/L]) were lower than current limits (for men, 667 nkat/L [40 U/L]; for women, 500 nkat/L [30 U/L]) and, during 6-month follow-up, showed superior sensitivity in identifying participants with HCV viremia (sensitivity, 76.3% [95 % CI, 69.1% to 83.6%] vs. 55% [CI, 46.4% to 63.5%]). The related tradeoff in specificity was acceptable (88.5% [CI, 79.2% to 94.6%] vs. 97.4% [91% to 99.7%]). The increased sensitivity targeted patients with minimal to mild histologic lesions.
  
  
  CONCLUSIONS
  In patients with chronic HCV infection or nonalcoholic fatty liver disease, revision of normal limits for ALT level is advisable.
authors.affiliation: Centro Trasfusionale e di Immunologia dei Trapianti, Laboratorio di Epidemiologia, Divisione di Ematologia, Istituto di Statistica Medica e Biometria, Cattedra di Gastroenterologia, Milan, Italy. dprati@yahoo.com
authors.forename: Daniele
authors.initials: D
authors.lastname: Prati
authors.forename: Emanuela
authors.initials: E
authors.lastname: Taioli
authors.forename: Alberto
authors.initials: A
authors.lastname: Zanella
authors.forename: Emanuela
authors.initials: E
authors.lastname: Della Torre
authors.forename: Sonia
authors.initials: S
authors.lastname: Butelli
authors.forename: Emanuela
authors.initials: E
authors.lastname: Del Vecchio
authors.forename: Luciana
authors.initials: L
authors.lastname: Vianello
authors.forename: Francesco
authors.initials: F
authors.lastname: Zanuso
authors.forename: Fulvio
authors.initials: F
authors.lastname: Mozzi
authors.forename: Silvano
authors.initials: S
authors.lastname: Milani
authors.forename: Dario
authors.initials: D
authors.lastname: Conte
authors.forename: Massimo
authors.initials: M
authors.lastname: Colombo
authors.forename: Girolamo
authors.initials: G
authors.lastname: Sirchia
mesh_terms: D000410:Alanine Transaminase / Q000097:blood*; D000704:Analysis of Variance; D001782:Blood Donors; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D004796:Clinical Enzyme Tests; D015331:Cohort Studies; D005260:Female; D006526:Hepatitis C / Q000175:diagnosis; D018937:Hepatitis C Antibodies / Q000097:blood; D006801:Humans; D008107:Liver Diseases / Q000097:blood / Q000175:diagnosis; D008297:Male; D012016:Reference Values; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014280:Triglycerides / Q000097:blood; D014766:Viremia / Q000175:diagnosis
chemical_list: D001786:Blood Glucose; D018937:Hepatitis C Antibodies; D014280:Triglycerides; D002784:Cholesterol; D000410:Alanine Transaminase