The Importance of Extension in the Screening Examination ofHIV Infection in Blood and Blood Components Donors in the Czech Republic

Overview

Introduction.
A mandatory HIV-1 antigen (HIV p24Ag) testing has been introduced in blood and bloodcomponents donors since April 2003 (with a transient period until October 2003) in the Czech Republic(CR), which supplements the previous anti-HIV-1, 2 testing. Study design and methods. 2,481 blood andblood components donors blood samples were tested by the combined assay for HIV antigen andanti-HIV-1,2 antibodies Genscreen_ Plus HIV Ag-Ab, Bio-Rad and by the antibody test Genscreen_ HIV1/2 version 2 simultaneously at Transfusion departments of the Masaryk’s Hospital in Ústí nad Labemand the University Hospital Královské Vinohrady in Prague in the years 2001-2002. The combined testwas also used for the testing of one control panel from the National Reference Laboratory for AIDS andone seroconversion panel. Results. In the tested donors samples, there were six initially reactivesamples in the antibody test and nine samples in the combined test. In these groups, repeated testingrevealed five and eight repeatedly reactive samples, respectively. No reactivity was confirmed aspositive or indeterminate in the National Reference Laboratory for AIDS. The results of panels testingwere in agreement and unambiguous. Specificity of the combined test was somewhat lower than in theantibody test (99,68% and 99,80%, respectively). Discussion and conclusion. The diagnostic window ofHIV infection is supposed to be shortened by 4,4 to 7 days by p24Ag testing in comparison to anti-HIV-1,2testing. The residual risk of HIV infection transfer by transfusion of anti-HIV-1,2-negative bloodcomponent is estimated to be 0.3 to 2.5 times for 106 samples. The detection rate of HIV p24Ag-positiveanti-HIV-1,2-negative sample in blood and blood components donors is in the range of one to 3.6x106 inGermany and in the U.S.A., one to 105 in Brazil and up to 16 per 105 donations in Thailand, respectively.In view of the low HIV infection prevalence in the population in CR the detection rate of such sampleis supposed to be one in 40 years with increased cost for the testing. The benefit of introducing HIV antigen testing in CR will probably be very low. The testing of HIV-1 by PCR (HIV-1 NAT) does not seemto be presently necessary.

Key words:
HIV p24 antigen, antibodies against HIV-1,2, the combined test, donors of blood and bloodcomponents