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Investigation for infectious markers of blood donors in Blood Establishment Hospital Č.B. a.s.
PÍCHOVÁ, Jana
The theme of the bachelor thesis is ?Infectious Disease Marker Testing of Blood Donors?. According legal rules, donated blood is tested for infectious agents of AIDS, syphilis and HBV, HCV. The risk of transmission of such diseases has been decreased in recent decades nevertheless it is still a threat to transfusion medicine. At the Transfusion Department of the České Budějovice Hospital, Inc., the samples of blood donors are tested in the Blood Donors Analytics Laboratory. At present, all the tests are performed on a single instrument Abbott Architect. Before testing on the Architect analyzer, viral markers were tested on the Abbott AxSYM instrument, while syphilis was tested via TP-PA method using a diagnostic kit by Serodia. The objective of the bachelor thesis is to compare the current testing systems with the previous ones, describe individual testing methods, count the numbers of reactive results and compare results of its confirmation tests, find out the frequency of reactive and positive results in new blood donors, verify results of the second confirmation of control samples. The thesis informs about basic criteria to select blood donors, individual infectious markers which cover the infectious diseases, in which a prolonged presence of the agents in blood occurs, and thus the transmission of the infection is possible. Further, the principles of methods used by the AxSYM analyzer, the Architect analyzer and Serodia TP-PA diagnostic kit are described. The samples showing the reactive results are sent to the National Reference Laboratory to be retested. In the period from 1st January 2011 to 31st December 2011 17,262 blood donors were tested using the AxSYM analyzer to detect HIV, HBsAg and HCV infections. The same number of the tests was performed also by TP-PA method to diagnose syphilis. In the period from 1st February 2012 to 31st January 2013, 18,346 of blood donor samples were tested to detect HIV, HBV, HCV and syphilis. 57 samples from the total number of tests performed on the AxSYM analyzer and TP-PA diagnostic kit were reactive in the year 2011. With the installation of the Architect analyzer the numbers of reactive samples increased more than twice, namely to 121 reactive samples. The largest increase in reactivity is evident in case of syphilis diagnostics. It was the similar with anti-HCV method. In both cases, the methods for antibodies detection are involved, and so it can be taken into account the interference with other non-specific antibodies. In the period of testing by TP-PA method on the AxSYM system, 20 reactive control samples, 10 reactive first time blood donors samples and 27 reactive regular donors samples were detected. After the changeover to Architect system, the numbers of reactive samples were increased unexpectedly in regular donors the most, namely up to 88 samples within the monitored period unlike 8 reactive samples in first time donors or 25 reactive control samples. In most cases, the confirmation test results of control samples are negative regardless the type of analyzer used for screening tests showing reactive results. The largest number of unclear results from the National Reference Laboratory (NRL) was observed with anti-HCV method. The NRL confirmed altogether 5 positive results for the monitored infection diseases, from which 4 were in new donors. This finding confirms the assumption that the first time donors are a risk group while with the regular blood donation the safety of blood transfusion is increasing. Based on all observed parameters the both analyzers can be regard as the safe systems for blood donors testing showing the sufficient specificity. The AxSYM analyzer was replaced by the newer Architect analyzer because of upgrading the machine equipment primarily. The chemiluminiscent test technology is preferred because of its high sensitivity, simplicity and reliability.
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