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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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External factors influencing the sensitivity of coagulation on prothrombin time - Quick test.
VOTRUBOVÁ, Hana
The aim of this work was to determine the length of the prothrombin time (PT) also called Quick test for stable sampling and whether this period has been dependent on the type of reagent.Methodological part of my work has been carried out in the Laboratory of Clinical Hematology Hospital in Ceske Budejovice, where I am employed. Blood samples have been received at the Department of Hospital Transfusion in Ceske Budejovice in the field of blood donors. The data set consisted of 20 "relatively" healthy blood donors, unburdened by any anticoagulant therapy or pathology of coagulation factors. Measurements were carried out on an automatic coagulation analyzer STA-R Evolution from Diagnostica Stago, which principle is based on the method of chronometric and photometric. The analyzer and reagent pipetting protocol Neoplastine CI Plus has been described. Reagents were kept and prepared according to instructions of the manufacturer as well as the set protocol sheets have been set. Preanalytical, analytical and post-analytical phase is also mentioned. During the work I respected SOP (standard operating procedure) of Laboratory of Clinical Hematology Hospital Ceske Budejovice. In the fourth part I compiled the results. All measured values at all time intervals were entered in the table (see Annex 1 Table 8). From the measured values, I calculated the average times of measurement values for each of the reagents and the determinant differences. As we can see from the tables (tab.1-5) Recombiplastin 2G shows the lowest average measuring values, in all the measured times. Increased time for most reagents are not large, but they exist. The differences between the measurements in relation to the first measurement have been calculated and brought into graphs (Fig.5-9) together with the standard deviation. After 12 hours, the lowest average difference measurements using reagents Neoplastine R 0,40% and standard deviation of 1,50. After 24 hours, reaching the lowest average difference Neoplastine R 0,80% with a standard deviation of 2,10. After 48 hours Thromborel S with the lowest average difference of 4,70% with a standard deviation of 2,90. After 72 hours from the first fixing smallest average difference in Recombiplastin 2G 9,30% with a standard deviation of 4,10. Individual differences in average times have been compared with the current validation protocol of Clinical Hematology Hospital Labs Ceske Budejovice as that given for the repeatability coefficient of variation for prothrombin time <1,5% (CV <1,5%). In time, 12 hours after sampling did not exceed the value of CV <1,5% only times specified reagents Neoplastine CI Plus, Neoplastine R and Recombiplastin 2G. At the time 24 hours of collection did not exceed this value Neoplastine R only. At time 48 and 72 hours after sampling exceeded all reagents CV <1,5%. This fact was in contradiction with Baglin study, which shifted the possibility of delayed analysis of up to 72 hours of collection. While Baglin determined stability according to the clinical significance of INR (international normalized ratio) between the reagents, in my work stability was determined according to more precise stability criteria, the coefficient of variation of repeatability. In the next section I calculated the average deviation of each reagent for all measurements. Top Thromborel S based 4,8%. The largest average deviation amounted Quick PT 8,9%. Compared thromboplastin average total deflection of the recombinant 5,6%. The tissue thromboplastin 6,5%. This difference was significantly influenced by one reagent, PT Quick. The hypothesis that the prothrombin time or the Quick test is stable for much longer than the usual two-hour interval has been confirmed, but this stability is affected by the thromboplastin.
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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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