Analytical and between-subject variation of thrombin generation measured by calibrated automated thrombography on plasma samples.
BACKGROUND
The Calibrated Automated Thrombography (CAT) is an in vitro thrombin generation (TG) assay that holds promise as a valuable tool within clinical diagnostics. However, the technique has a considerable analytical variation, and we therefore, investigated the analytical and between-subject variation of CAT systematically. Moreover, we assess the application of an internal standard for normalization to diminish variation.


METHODS
20 healthy volunteers donated one blood sample which was subsequently centrifuged, aliquoted and stored at -80 °C prior to analysis. The analytical variation was determined on eight runs, where plasma from the same seven volunteers was processed in triplicates, and for the between-subject variation, TG analysis was performed on plasma from all 20 volunteers. The trigger reagents used for the TG assays included both PPP reagent containing 5 pM tissue factor (TF) and PPPlow with 1 pM TF. Plasma, drawn from a single donor, was applied to all plates as an internal standard for each TG analysis, which subsequently was used for normalization.


RESULTS
The total analytical variation for TG analysis performed with PPPlow reagent is 3-14% and 9-13% for PPP reagent. This variation can be minimally reduced by using an internal standard but mainly for ETP (endogenous thrombin potential). The between-subject variation is higher when using PPPlow than PPP and this variation is considerable higher than the analytical variation.


CONCLUSION
TG has a rather high inherent analytical variation but considerable lower than the between-subject variation when using PPPlow as reagent.
['Kristensen|Anne F|AF|0000-0002-6961-2246', 'Kristensen|Søren R|SR|', 'Falkmer|Ursula|U|', 'Münster|Anna-Marie B|AB|', 'Pedersen|Shona|S|']
D000328:Adult D000704:Analysis of Variance D001780:Blood Coagulation Tests D002138:Calibration D005260:Female D064368:Healthy Volunteers D006801:Humans D008297:Male D008875:Middle Aged D015588:Observer Variation D015203:Reproducibility of Results D013916:Thrombelastography D013917:Thrombin D013925:Thromboplastin
between-subject variation thrombin thrombin generation Analytical variation blood coagulation blood coagulation test