Within-subject and between-subject biological variation of prothrombin time and activated partial thromboplastin time.
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.
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Laboratori d'Anàlisis Clíniques, Hospital de Viladecans, Spain.
Miró
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Fuentes-Arderiu
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D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D011517:Prothrombin Time