title: Distribution of plasma cardiac troponin I values in healthy subjects: pathophysiological considerations.
abstract: BACKGROUND
  The aim of this study was to evaluate the distribution of cardiac troponin I (cTnI) values, measured by the ADVIA TnI-Ultra method (Siemens Medical Solutions Diagnostics SrL) in healthy subjects and to characterize its relation to gender, age, as well as to N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP).
  
  
  METHODS
  A Caucasian population of 692 healthy subjects (311 males and 381 females) with a mean (SD) age of 45.3 (17.3) years [range 11-89 years; females 46.5 (17.3) years, males 43.8 (17.1) years] was enrolled. The presence of cardiac or systemic acute or chronic diseases was excluded by history and accurate clinical evaluation.
  
  
  RESULTS
  A significant difference was found between the cTnI values in men and women (men: median 0.012 microg/L, range from undetectable values to 0.196 microg/L; women: median 0.008 microg/L, range from undetectable values to 0.130 microg/L; p<0.0001 by Mann-Whitney U-test). When a multiple regression analysis was performed, NT-proBNP, gender and age significantly contributed to the regression with cTnI (R=0.444, p<0.0001).
  
  
  CONCLUSIONS
  Our data indicate that cut-off values, based on the 99th percentile of cTnI distribution in apparently healthy subjects, can significantly vary according to age and gender of the reference population.
authors.affiliation: Fondazione Gabriele Monasterio and CNR Institute of Clinical Physiology, Pisa, Italy. clerico@ifc.cnr.it
authors.forename: Aldo
authors.initials: A
authors.lastname: Clerico
authors.forename: Antonio
authors.initials: A
authors.lastname: Fortunato
authors.forename: Andrea
authors.initials: A
authors.lastname: Ripoli
authors.forename: Concetta
authors.initials: C
authors.lastname: Prontera
authors.forename: Gian Carlo
authors.initials: GC
authors.lastname: Zucchelli
authors.forename: Michele
authors.initials: M
authors.lastname: Emdin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D012016:Reference Values; D012727:Sex Characteristics; D019210:Troponin I / Q000097:blood*
chemical_list: D010446:Peptide Fragments; D019210:Troponin I; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain