title: In normal controls, both age and gender affect coagulability as measured by thrombelastography.
abstract: BACKGROUND
  Our objective was to analyze the effects of age, gender, and the use of oral contraceptives (OCs) on coagulation using thrombelastography (TEG), a single test to analyze both plasma coagulation factors and cellular elements in whole blood.
  
  
  METHODS
  TEG variables were measured in native whole blood and in recalcified citrated blood from 120 healthy adults (60 men and 60 women) with various ages and in an additional 29 healthy women using OCs.
  
  
  RESULTS
  We observed hypercoagulability in women compared with men and in women using OCs compared with age-matched nonusers. Moreover, we found hypercoagulability with aging. Using the method of Bland and Altman (Lancet 1986;1:307-10), we demonstrated no correlation between TEG measurements in native and recalcified citrated blood.
  
  
  CONCLUSIONS
  Aging, female gender, use of OCs, and low-normal hematocrit levels have significant procoagulant effects. TEG measurements in native and recalcified citrated blood are not interchangeable, as indicated by differences between the 2 measurements ranging from 20% in maximal amplitude to 246% in clotting time. Furthermore, the limits of agreement strongly exceeded clinical acceptability to conclude interchangeability.
authors.affiliation: Department of Hematology, University Medical Center Groningen, Groningen 9700 RB, The Netherlands. j.t.m.de.wolf@int.umcg.nl
authors.forename: Wilfried W H
authors.initials: WW
authors.lastname: Roeloffzen
authors.forename: Hanneke C
authors.initials: HC
authors.lastname: Kluin-Nelemans
authors.forename: Andre B
authors.initials: AB
authors.lastname: Mulder
authors.forename: Nic J G M
authors.initials: NJ
authors.lastname: Veeger
authors.forename: Lotte
authors.initials: L
authors.lastname: Bosman
authors.forename: Joost Th M
authors.initials: JT
authors.lastname: de Wolf
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D001777:Blood Coagulation / Q000502:physiology*; D001800:Blood Specimen Collection; D002951:Citrates / Q000737:chemistry; D005260:Female; D005337:Fibrin / Q000737:chemistry; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007202:Indicators and Reagents; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D013048:Specimen Handling; D013916:Thrombelastography; D013927:Thrombosis / Q000097:blood; D055815:Young Adult
chemical_list: D002951:Citrates; D006454:Hemoglobins; D007202:Indicators and Reagents; D005337:Fibrin