engleski

Specificity of Automated Blood Screening Assays developed for the new Abbott ALINITY S System

Background: While serological assays for blood and plasma screening must have a high sensitivity, specificity of the assays is equally important. When blood and plasma centers consider switching to a new method, they are well aware that this may result in a temporary or permanent deferral of donors if the new method is less specific than the previous method that was used for donor testing. This is a major concern especially for those centers that have a very high proportion of multiple time whole blood or plasma donors. Aims: To evaluate the initial (IRR) and repeat reactive rate (RRR), and specificity of the prototype assays developed for the new Abbott Alinity s System at two sites in Europe using routine surplus samples from whole blood donors (serum or plasma). Initially reactive samples are defined as those that did not test reactive upon repeat testing, whereas the rate of repeatedly reactive samples is the percentage of samples that are repeatedly reactive but not found positive by confirmatory testing. Methods: Serum and plasma samples from routine whole blood donors were tested by commercially available methods and the following prototype Alinity s assays: HIV Ag/Ab Combo (n=1856), HBsAg (n=1925), Anti-HCV (n=1924), Anti-HBc (n=1857), Syphilis (n=2708) and HTLV I/II (n=2543). Initial reactive results and any samples with a discrepant result to the routine method were retested in duplicate and subject to confirmatory testing. Results: For the Alinity s HBsAg, Anti-HCV and Syphilis assays, all samples tested initially non-reactive, and the specificity of these assays was determined to be 100 %. The Alinity s HIV Ag/Ab Combo assay had one initially reactive sample that turned negative upon retesting in duplicate, for a specificity of 100 %. Nine samples were found repeatedly reactive upon testing with Alinity s Anti-HBc, all of which were confirmed positive upon subsequent testing. For Alinity s HTLV I/II, two samples were initially and repeatedly reactive but negative by confirmatory testing, therefore reducing the specificity of this test to 99, 92 %. Summary / Conclusions: The prototype screening assays developed for use with the new Alinity s System showed very good specificity when using samples from populations with a high percentage of multiple time donors. These data indicate that the introduction of the newly developed Alinity s screening assays will not cause unnecessary donor deferral, not even temporarily.

specificity ; blood screening assays ; Abbott Alinity S System

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