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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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