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Comparison of the results of basic coagulation tests carried out in three different laboratories on the same sample of blood
FÁLOVÁ, Alena
Basic coagulation tests are carried out in every laboratory of hematology. Every patient who is about to undergo a surgery, or is treated with anticoagulants, should be examined this way. Coagulation tests allows to find out, if the patient is suffering from outer or from inner coagulation cascade disorder. Final diagnosis is carried out using specialized tests. The basic tests include protrombin time, activated parcial tromboplastin time, and fibrinogene. The principle of coagulation tests is determination of the time needed for detection of fibrin fiber after addition of reagent to the sample of tested plasma. Tests used in hemostasis can be global, group and specific. For the test, test tubes with an antikoagulant are used. In hemostasis, the antikoagulant used is trisodium citrate. It is always necessary to keep the same blood/citrate ratio. The preanalytical part, which consists of specific actions the sample undergoes from its obtaining to the analysis itself, is also very important. Nowadays, the coagulation tests are run in laboratories using multifunctional analysators. Blood samples are obtained from a vein. Small, portable coagulometers are used for measuring protrombin time for patients treated with anticoagulants. Blood for this test can be obtained from the fingertip. This thesis is focused on comparing the measurment of a sample on three different coagulometers. Different tromboplastins with different ISI (International Sensitivity Index) were used. Reagents for activated parcial tromboplastin time were also purchased from different producers. In this bachelor thesis, fifty randomly chosen samples were tested, because not every application form has the patients diagnosis stated. Every sample was tested that very day, within four hours from taking the blood. Samples were primarily tested in laboratory Synlab czech s.r.o., using coagulometer Sysmex CA. Other measurments were carried out in laboratory Stafila s.r.o. using coaguometer ACL Elite PRO and in laboratory Medipont s.r.o. using coagulometer START 4. All measurments were statisticaly evaluated. Average values and standard deviation were calculated, and shows, that the values does not differ significantly. Level of significance in INR test (international normalised ratio) and in activated parcial tromboplastin time was evaluated as statisticaly significant, yet without bigger clinical importance. Only in protrombine time, measured in seconds, results from coagulometers does not differ. The same can be applied when comparing coagulometers with each other. Based on my findings, it is recomended for the doctors to use the same laboratory for testing the protrombin time and activated parcial tromboplastin time. At the same time, it is necessary to say, that the differences measured in this thesis are so minor, that they have no practical clinical importance.
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Coagulation examination
ROJDLOVÁ, Lenka
Today coagulative examination belongs to the hematological tests which are often required namely as part of pre-surgery examinations and in frame of anti-coagulative therapy observation. The basic coagulative examinations are activated partial tromboplastine time (aPTT), protrombinal time (PT), determination of blood platelets amount and the time of bleeding (Duke´s time). These examinations enable us to find out whether a disorder of internal or external way of coagulative cascade occurs or if it applies to trombocytopathy or a functional blood platelets disorder. This thesis focuses on research what is the influence on the aPTT examination and PT time interval result between the patient´s blood taking and its laboratory analysis. The coagulative cascade is stated in the theoretical part along with its main ways according to the latest literary data and additions. The following chapter deals with coagulative factors which take part in the coagulative cascade activation. Attention is also dedicated to blood platelets and next possible pathology of haemostasia. The biggest part deals with the methods of coagulative determination. The thesis focuses also on analytical processes during coagulation examination, as well as the significance of non-analytic examination phase is emphasized here. The practical and research part of my thesis was performed in the laboratory Laboma, s.r.o. České Budějovice, where I examined 50 random samples chosen of daily routine operation from various patients. In all these samples coagulative examination with aPTT and PT tests was carried out at different time intervals after the blood taking. The aim was to verify how final values of the stated coagulation examinations change if these are carried out after a longer time than recommended in the laboratory practice. In both used coagulation tests, before the sample analysis, verification was made to prove the outcome exactness. Verification is also the practical part of this thesis. On the basis of measured outcomes, I carried out the statistical evaluation which shows how measured values differ depending on the blood taking time interval and whether it is possible to perform these coagulation examinations in a different time interval from blood taking.
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