12/29/2023 0 Comments History of sequential screeningThus there is potential for cost savings, especially if the more expensive assays do not need to be performed on donations that have already tested positive for HBsAg. No tests for these viral markers would be performed on the donations that test reactive on the HBsAg screening test. In this situation, only HBsAg negative donations would then be tested for HIV antigen-antibody, anti-HCV and syphilis. Sequential screening is sometimes used in countries where the prevalence of one TTI is higher than others for instance, HBsAg might be screened for first when the prevalence of hepatitis B is higher than the prevalence of HIV and HCV. ![]() The screening strategy for determining the test or tests that are undertaken first will be influenced by the prevalence of infections in the blood donor population. If a reactive result is obtained, no further testing is performed on this donation. Some laboratories may use sequential screening by initially testing for one or two infection markers. Depending on the algorithm used by the laboratory, the donation is then either discarded or repeat testing is performed. Initially reactive donations are segregated and quarantined. The main reason for this is to reduce the time needed for screening so that the blood or blood components, especially labile components such as platelets, can be released in a timely manner. The results of all tests performed for infection markers for TTIs and blood group serology should be evaluated when making final decisions on the release of blood units for therapeutic use.īlood transfusion services routinely screen for TTI markers (HIV antigen-antibody, HBsAg, anti-HCV and syphilis) at the same time. The appropriate confirmatory testing strategy for blood donor management should be applied before notifying donors of their infectivity status (see Section 6). Blood screening strategies are designed to assure the safety of blood units, but should not be used for notifying blood donors of reactive test results. The objective of blood screening is to detect markers of infection in order to prevent the release of infected blood and blood components for clinical use. The performance of laboratory tests in a quality environment with competent staff and a functional documentation system will minimize the risk of analytical and transcription errors, particularly false negative results. ![]() Laboratory staff should always adhere to the national screening strategy, algorithm and standardized procedures when conducting the tests and analysing the results. ![]() These systems will ensure that the correct results are allocated to each donation and prevent errors resulting in the transfusion of an unsafe unit. The BTS should also have appropriate, validated systems for linking all test results to the correct donations and donors so that donors' records can be reviewed each time they come to donate. All tests on blood samples should be performed and recorded in accordance with standardized procedures in laboratories that are properly equipped to undertake them.Īll blood samples, donations and components should be correctly labelled to ensure correct identification throughout the screening process. Laboratory screening for TTIs should be performed on blood samples collected at the time of donation. Based on the screening results, they should either be released for clinical or manufacturing use or be discarded. The screening of donated blood and the quarantine of blood and blood components represent critical processes that should be followed to ensure that blood units are safe.
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