title: Laboratory coagulation parameters in extremely premature infants born earlier than 27 gestational weeks upon admission to a neonatal intensive care unit.
abstract: BACKGROUND
  Few published data exist to guide interpretation of coagulation times in extremely premature infants.
  
  
  OBJECTIVE
  To determine coagulation reference ranges on day 1 of life in extremely premature infants.
  
  
  METHODS
  A retrospective review of day 1 coagulation tests was performed in 144 infants <27 weeks' gestation between 2004 and 2010 in a tertiary neonatal unit. Samples were drawn through a non-heparinized umbilical or peripheral venous catheter as part of routine clinical care.
  
  
  RESULTS
  Mean (SD) and median (range) prothrombin times (PT) of 21.5 (5.3) and 20.2 (13.3-39) s, respectively, activated partial thromboplastin times (APTT) of 75.2 (27.8) and 67.4 (34.9-191.6) s, respectively, and plasma fibrinogen levels of 1.9 (1.1) and 1.4 (0.5-4.8) g/l, respectively, were reported. Using reference intervals derived from the 2.5th to 97.5th centiles, ranges of 14.4-36.7 s, 40.5-158.5 s and 0.7-4.8 g/l were determined for PT, APTT and plasma fibrinogen levels, respectively. In a subcohort with grade 0-2 intraventricular haemorrhage (n = 92), mean PT and APTT were 20.9 and 71.3 s, respectively, versus mean PT and APTT of 23.1 and 88.4 s (p = 0.06 and p = 0.03), respectively for those with grade 3-4 intraventricular haemorrhage. Mean PT and APTT in a cohort of infants defined to be small for gestational age were 22 and 76.8 s. These results did not differ significantly from non-small for gestational age infants, with a mean PT and APTT of 19.5 and 73.4 s (p = 0.09 and p = 0.7).
  
  
  CONCLUSIONS
  Reference ranges based on retrospective data were determined for PT, APTT and fibrinogen in a large cohort of extremely preterm infants.
authors.affiliation: Department of Paediatrics, Royal College of Surgeons, Dublin, Ireland.
authors.forename: Elaine
authors.initials: E
authors.lastname: Neary
authors.forename: Ike
authors.initials: I
authors.lastname: Okafor
authors.forename: Faten
authors.initials: F
authors.lastname: Al-Awaysheh
authors.forename: Colin
authors.initials: C
authors.lastname: Kirkham
authors.forename: Katie
authors.initials: K
authors.lastname: Sheehan
authors.forename: Ciaran
authors.initials: C
authors.lastname: Mooney
authors.forename: Adrienne
authors.initials: A
authors.lastname: Foran
authors.forename: J D
authors.initials: JD
authors.lastname: Corcoran
authors.forename: Fionnuala
authors.initials: F
authors.lastname: Ni Ainle
authors.forename: Melanie
authors.initials: M
authors.lastname: Cotter
authors.forename: Naomi
authors.initials: N
authors.lastname: McCallion
mesh_terms: D001777:Blood Coagulation / Q000502:physiology*; D001780:Blood Coagulation Tests / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D005340:Fibrinogen / Q000032:analysis*; D005865:Gestational Age; D006801:Humans; D062071:Infant, Extremely Premature / Q000097:blood*; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000097:blood*; D007363:Intensive Care Units, Neonatal; D008297:Male; D010314:Partial Thromboplastin Time; D011517:Prothrombin Time; D012016:Reference Values; D012189:Retrospective Studies
chemical_list: D005340:Fibrinogen