title: The calculation of the cardiac troponin T 99th percentile of the reference population is affected by age, gender, and population selection: a multicenter study in Italy.
abstract: BACKGROUND
  The aim of this study is to determine the 99th upper-reference limit (URL) for cardiac troponin T (cTnT) in Italian apparently healthy subjects.
  
  
  METHODS
  The reference population was selected from 5 cities: Bolzano (n=290), Milano (CAMELIA-Study, n=287), Montignoso (MEHLP-Study, n=306), Pisa (n=182), and Reggio Calabria (MAREA-Study, n=535). Subjects having cardiac/systemic acute/chronic diseases were excluded. Participants to MEHLP project underwent cardiac imaging investigation. High-sensitive cTnT was measured with Cobas-e411 (Roche Diagnostics).
  
  
  RESULTS
  We enrolled 1600 healthy subjects [54.6% males; age range 10-90years; mean (SD): 36.4 (21.2) years], including 34.6% aged <20years, 54.5% between 20 and 64years, and 10.9% over 65years. In the youngest the 99th URL was 10.9ng/L in males and 6.8ng/L in females; in adults 23.2ng/L and 10.2ng/L; and in elderly 36.8ng/L and 28.6ng/L. After the exclusion of outliers the 99th URL values were significantly decreased (P<0.05) in particular those of the oldest (13.8ng/L and 14ng/L). MEHLP participants were divided in healthy and asymptomatic, according to known cardiovascular risk factors (HDL, LDL, glucose, C-reactive protein): the 99th URL of cTnT values of these subgroups was significantly different (19.5 vs. 22.7, P<0.05).
  
  
  CONCLUSIONS
  99th URL of cTnT values was strongly affected by age, gender, selection of subjects and the statistical evaluation of outliers.
authors.affiliation: Scuola Superiora Sant'Anna, Pisa, Italy; Fondazione Toscana G. Monasterio, Pisa, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Franzini
authors.affiliation: Scuola Superiora Sant'Anna, Pisa, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Lorenzoni
authors.affiliation: Scuola Superiora Sant'Anna, Pisa, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Masotti
authors.affiliation: Fondazione Toscana G. Monasterio, Pisa, Italy.
authors.forename: Concetta
authors.initials: C
authors.lastname: Prontera
authors.affiliation: Fondazione Toscana G. Monasterio, Pisa, Italy.
authors.forename: Dante
authors.initials: D
authors.lastname: Chiappino
authors.affiliation: Fondazione Toscana G. Monasterio, Pisa, Italy.
authors.forename: Daniele Della
authors.initials: DD
authors.lastname: Latta
authors.affiliation: Clinical Biochemical Laboratory, San Maurizio Regional Hospital, Bolzano, ltaly.
authors.forename: Massimo
authors.initials: M
authors.lastname: Daves
authors.affiliation: Clinical Biochemical Laboratory, San Maurizio Regional Hospital, Bolzano, ltaly.
authors.forename: Irene
authors.initials: I
authors.lastname: Deluggi
authors.affiliation: Department of lnternal Medicine and Liver Unit, School of Medicine San Paolo, University of Milan, Milan, ltaly.
authors.forename: Massimo
authors.initials: M
authors.lastname: Zuin
authors.affiliation: Centro Nazionale di Epidemiologia, Sorveglianza e Promozione della Salute, Istituto Superiore di Sanita', Roma, Italy.
authors.forename: Luigina
authors.initials: L
authors.lastname: Ferrigno
authors.affiliation: Centro Nazionale di Epidemiologia, Sorveglianza e Promozione della Salute, Istituto Superiore di Sanita', Roma, Italy.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Mele
authors.affiliation: Scientific Directorate, Regina Elena Cancer Institute, Roma Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Marcucci
authors.affiliation: Hepatology Association of Calabria, Pellaro, RC Italy.
authors.forename: Carmelo A
authors.initials: CA
authors.lastname: Caserta
authors.affiliation: Hepatology Association of Calabria, Pellaro, RC Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Surace
authors.affiliation: Hepatology Association of Calabria, Pellaro, RC Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Messineo
authors.affiliation: Scuola Superiora Sant'Anna, Pisa, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Turchetti
authors.affiliation: Fondazione Toscana G. Monasterio, Pisa, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Passino
authors.affiliation: Fondazione Toscana G. Monasterio, Pisa, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Emdin
authors.affiliation: Scuola Superiora Sant'Anna, Pisa, Italy; Fondazione Toscana G. Monasterio, Pisa, Italy.
authors.forename: Aldo
authors.initials: A
authors.lastname: Clerico
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism; D002097:C-Reactive Protein / Q000378:metabolism; D002648:Child; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D012016:Reference Values; D012307:Risk Factors; D012737:Sex Factors; D020107:Troponin T / Q000097:blood*
chemical_list: D001786:Blood Glucose; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D020107:Troponin T; D002097:C-Reactive Protein
keywords: 99th upper reference limit; Cardiac troponin T; Outlier calculation; Reference population