title: Within-subject and between-subject biological variation of prothrombin time and activated partial thromboplastin time.
abstract: The within-subject and between-subject biological variation of prothrombin time (PT) and activated partial thromboplastin time (APTT) have been studied in a group of 19 women and 20 men over a period of 9 months. All measurements were performed with a mechanical coagulometer. The between-subject coefficients of variation were 6.8% for PT and 8.9% for APTT. The medians and the 90th percentiles of within-subject coefficients of variation were 1.7% and 5.9%, respectively, for PT, and 0.0% and 6.1% for APTT. These data were used to calculate the critical difference for significant change detection and the desirable between-day imprecision.
authors.affiliation: Laboratori d'Anàlisis Clíniques, Hospital de Viladecans, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Dot
authors.forename: J
authors.initials: J
authors.lastname: Miró
authors.forename: X
authors.initials: X
authors.lastname: Fuentes-Arderiu
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D011517:Prothrombin Time