title: Routine coagulation tests in newborn and young infants.
abstract: BACKGROUND
  The diagnostic approach to haemostatic defects in the newborn is challenging and requires appropriate interpretation of coagulation tests according to reference values dependent on the postnatal age.
  
  
  METHODS
  This investigation was designed to study the postnatal development of the human coagulation system in newborn infants and to develop appropriate reference ranges for prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen (FBG) according at the day of birth and for the following postnatal period (days 1, 2, 3, 4, 5, 6, from 7 to 10 and from 11 to 44).
  
  
  RESULTS
  The mean FBG value was already within the adult reference range in newborns at birth, the mean PT value fell within the adult reference range in infants aged 4 days or more, whereas the mean APTT value was still higher than the upper limit of the adult reference range in infants aged between 11 and 20 days. The prevalence of infants with pathological values according to the actual adult reference ranges was limited for FBG (from 24 to 7%), decreased from 92 to 8% in infants aged 0 and 11-20 days for PT, but remained elevated throughout the observational period for APTT (from 94 to 71%).
  
  
  CONCLUSIONS
  The results of the present investigation demonstrate that the actual adult reference ranges for coagulation screening tests, especially PT and APTT, cannot be applied to newborns and young infants.
authors.affiliation: Sezione di Chimica Clinica, Dipartimento di Scienze Morfologico-Biomediche, Ospedale Policlinico G.B. Rossi, Università degli Studi di Verona, Piazzale Scuro, 10, 37134 Verona, Italy. ulippi@tin.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lippi
authors.forename: Gian Luca
authors.initials: GL
authors.lastname: Salvagno
authors.forename: Simone
authors.initials: S
authors.lastname: Rugolotto
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Chiaffoni
authors.forename: Ezio Maria
authors.initials: EM
authors.lastname: Padovani
authors.forename: Massimo
authors.initials: M
authors.lastname: Franchini
authors.forename: Gian Cesare
authors.initials: GC
authors.lastname: Guidi
mesh_terms: D000328:Adult; D001777:Blood Coagulation / Q000502:physiology; D001780:Blood Coagulation Tests / Q000592:standards*; D005340:Fibrinogen; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008403:Mass Screening; D010314:Partial Thromboplastin Time; D011517:Prothrombin Time; D012016:Reference Values
chemical_list: D005340:Fibrinogen