engleski

Influence of saliva on the results of laboratory coagulation tests

Introduction: Oral wounds inevitably come into contact with saliva which can affect time needed for bleeding to stop. Its effect can be nonspecific, related to dilution of blood, or, potentially, mediated by salivary factors that affect haemostasis directly. The aim of this study was to examine if mixing blood with individual's saliva would influence the rate of its coagulation measured by global haemostatic tests, prothrombin time (PT) and activated partial thromboplastin time (aPTT). Materials and Methods: The study included 30 healthy nonsmoking volunteers who maintain good oral hygiene and health. Paired blood and unstimulated saliva samples were obtained from each study participant and PT and aPTT were determined in blood, blood+saliva and blood+water mixtures. Coagulation tests were performed using the mechanical clot detection method. Results: PT was significantly longer and PT% significantly lower in both blood+saliva and blood+water mixtures compared to blood alone. However, aPTT was significantly longer only in blood+water mixture compared to blood. Conclusions: Equally prolonged PT in both mixtures could suggest that both saliva and water prolong coagulation evenly due to their nonspecific effect of blood dilution (i.e. dilution of blood procoagulants). However, the finding that aPTT was significantly prolonged only when blood was mixed with water could indicate presence of tissue factor (TF) in saliva. Its concentration is likely too low to influence the results of PT. However, as reagents for performing aPTT do not contain recombinant TF, salivary TF could be an additional factor in stimulating coagulation thereby counteracting the anticoagulant effect of dilution.

activated partial thromboplastin time ; blood coagulation ; prothrombin time ; unstimulated saliva

nije evidentirano