Warfarin är ett läkemedel som används för att förhindra att högriskpatienter såsom de med förmaksflimmer får tromboembolism. Denna verkan uppnås genom att hämma de K-vitaminberoende faktorerna VII, X och protrombin och på så sätt minska blodets förmåga att koagulera. Att hitta rätt dosering av läkemedlet för warfarinbehandlade patienter har visat sig vara svårt eftersom det kräver regelbunden provtagning och påverkas av mat- och levnadsvanor. Det vanligaste sättet att mäta protrombinkomplexhalten är med venös plasma men det är även möjligt att använda sig av kapillär plasma. Helblod kan användas för mekaniska metoder som inte använder sig av optisk detektion. Fördelen är att helblod inte kräver centrifugering. Studiens syfte var att undersöka om det fanns en signifikant skillnad (p≤0,05) mellan helblod och plasma som används i den nuvarande metoden för kapillära prover och om det finns en skillnad i stabiliteten av dessa prov. Dubbla prover togs från 30 warfarinbehandlade patienter och 5 icke warfarinbehandlade individer. Ett av proven centrifugerades och analyserades på plasma, det andra analyserades på helblod. Resultaten visade att det fanns en signifikant skillnad (p≤0,05) mellan metoderna. Bland-Altman diagrammet visade att 95 % av helblodsproverna inte var högre än 0,25 INR och lägre än 0,14 INR. Detta har en låg klinisk inverkan. 4 Proverna förvarades i rumstemperatur i upp till 24 timmar och analyserades sedan om. Ingen förändring över 10 % kunde observeras i hållbarheten. Studien visade att trots att det finns en signifikant skillnad är det möjligt att ersätta den nuvarande metoden med plasma och använda helblod istället. / Warfarin is a drug used to prevent high-risk patients such as those with atrial fibrillation from thromboembolisms. This effect is achieved by suppressing vitamin-K dependent factors VII, X and prothrombin and therefore decreasing the bloods ability to clot. Finding the right dosage of the drug for warfarin treated patients has proven difficult, as it demands regular blood draws to monitor their prothrombin complex level, which is affected by dietary and living habits. The most common way to measure prothrombin complex levels is by using venous plasma but it is also possible to use capillary plasma. Whole blood can be used for mechanical methods, which don’t use optical detection. The benefit is that whole blood doesn’t require centrifugation. The aim of this study was to investigate if there was a significant difference (p≤0,05) between using whole blood and plasma which is the existing method for capillary sample and also if there is any differences between the stability of these samples. Double samples from 30 warfarin treated patients and 5 non-treated persons were taken. One of the samples were centrifuged and analyzed on plasma and the other analyzed on whole blood. The results showed that there was a significant difference (p≤0,05) between the methods. Bland-Altman plot comparison showed that 95 % of the whole blood samples would not be higher than 0,25 INR and lower than 0,14 INR. This has low clinical impact. The samples were stored at room temperature for up to 24 hours and reanalyzed. No changes over 10 % in INR values were observed. This study showed that even though there is a significant difference, it is possible to replace the existing method which using plasma with the whole blood instead.

In Introduction, the author of this dissertation deals with postoperative venous thromboembolism (VTE), hereditary and acquired risk factors, prophylaxis regimens and recent recommendation of VTE prevention in surgery. In Practical part of this work the author assesses the risk of VTE in surgical patients according to risk assessment model. Genetic testing is carried out in all patients to determine the incidence of hereditary thrombophilia and coagulation markers are measured in 28-days postoperative period. Prevalence of VTE in 1-year postoperative period is observed. The results are analysed in group of patients with benign disease (hernia and gallstone disease) and group of patients with malignancy (colorectal cancer and pancreatic cancer) separately. The objective of this work is to determine the incidence of the most frequent thrombophilic mutations (factor V Leiden mutation and protrombin G20210A mutation) and assess the impact of hereditary thrombophilia on incidence of postoperative venous thromboembolism in general surgery. Validation of venous thrombosis risk assessment model recommended by Czech Society for Thrombosis and Hemostasis is further objective.

In Introduction, the author of this dissertation deals with postoperative venous thromboembolism (VTE), hereditary and acquired risk factors, prophylaxis regimens and recent recommendation of VTE prevention in surgery. In Practical part of this work the author assesses the risk of VTE in surgical patients according to risk assessment model. Genetic testing is carried out in all patients to determine the incidence of hereditary thrombophilia and coagulation markers are measured in 28-days postoperative period. Prevalence of VTE in 1-year postoperative period is observed. The results are analysed in group of patients with benign disease (hernia and gallstone disease) and group of patients with malignancy (colorectal cancer and pancreatic cancer) separately. The objective of this work is to determine the incidence of the most frequent thrombophilic mutations (factor V Leiden mutation and protrombin G20210A mutation) and assess the impact of hereditary thrombophilia on incidence of postoperative venous thromboembolism in general surgery. Validation of venous thrombosis risk assessment model recommended by Czech Society for Thrombosis and Hemostasis is further objective.