title: Gestational age-specific reference intervals for routine haemostatic assays during normal pregnancy.
abstract: BACKGROUND
  Human gestation is a period that requires particular considerations. During this period, the blood of parturient women is in a hypercoagulable state. Therefore, reference ranges based on healthy men or nonpregnant women are not optimal for informing clinical decisions during pregnancy. There are few reports of gestational age-specific reference intervals; therefore, it is essential to explore such reference ranges.
  
  
  METHODS
  Four analytes, including prothrombin time (PT), thrombin time (TT), activated partial thromboplastin time (APTT) and fibrinogen (Fib), were assayed on an ACL TOP automatic coagulation analyser using plasma samples from 1130 pregnant women. Outliers were excluded from each group.
  
  
  RESULTS
  The reference ranges for PT, TT, APTT, and Fib at ≤12 weeks' gestation were 8.87-12.23, 11.84-18.00, 27.58-41.87, 2.00-4.23, respectively. At 13-20 weeks' gestation the ranges were 8.37-13.20, 12.00-17.56, 26.26-40.85, 2.35-4.90, respectively. At 21-27 weeks' gestation the ranges were 8.37-12.79, 11.94-17.33, 25.04-40.61, 2.38-5.19, respectively. At 28-35 weeks' gestation the ranges were 8.10-11.90, 12.27-17.56, 23.90-43.34, 2.35-4.90, respectively. At 36-42 weeks' gestation the ranges were 8.50-11.05, 10.08-16.60, 25.59-42.53, 2.48-5.06, respectively.
  
  
  CONCLUSIONS
  The above-established gestational age-specific reference intervals may assist clinicians in making accurate clinical decisions and can be adopted in other laboratories after further validation.
authors: Department of Clinical Laboratory, Zhengzhou University Third Hospital, Zhengzhou, China.
authors: Junjie
authors: J
authors: Liu
authors: EnWu
authors: E
authors: Yuan
authors: Li
authors: L
authors: Lee
mesh_terms: D000328:Adult; D001780:Blood Coagulation Tests / Q000592:standards*; D005260:Female; D005865:Gestational Age; D006487:Hemostasis; D006801:Humans; D011247:Pregnancy / Q000502:physiology*; D012016:Reference Values