Biological variation in tPA-induced plasma clot lysis time

Simone Talens, Joyce J. M. C. Malfliet, Goran Rudez, Henri M. H. Spronk, Nicole A. H. Janssen, Piet Meijer, Cornelis Kluft, Moniek P. M. de Maat, Dingeman C. Rijken*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Hypofibrinolysis is a risk factor for venous and arterial thrombosis, and can be assessed by using a turbidimetric tPA-induced clot lysis time (CLT) assay. Biological variation in clot lysis time may affect the interpretation and usefulness of CLT as a risk factor for thrombosis. Sufficient information about assay variation and biological variation in CLT is not yet available. Thus, this study aimed to determine the analytical, within-subject and between-subject variation in CLT. We collected blood samples from 40 healthy individuals throughout a period of one year (average 11.8 visits) and determined the CLT of each plasma sample in duplicate. The mean (+/- SD) CLT was 83.8 (+/- 11.1) minutes. The coefficients of variation for total variation, analytical variation, within-subject variation and between-subject variation were 13.4%, 2.6%, 8.2% and 10.2%, respectively. One measurement can estimate the CLT that does not deviate more than 20% from its true value. The contribution of analytical variation to the within-subject variation was 5.0%, the index of individuality was 0.84 and the reference change value was 23.8%. The CLT was longer in the morning compared to the afternoon and was slightly longer in older individuals (> 40 years) compared to younger (
Original languageEnglish
Pages (from-to)640-646
JournalThrombosis and Haemostasis
Issue number4
Publication statusPublished - Oct 2012


  • CLT
  • biological variation
  • fibrinolysis

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