Prevalence of human immunodeficiency virus type 1 p24 antigen in U.S. blood donors--an assessment of the efficacy of testing in donor screening. The HIV-Antigen Study Group.
BACKGROUND
We performed a multicenter study in 1989 to determine whether screening whole-blood donors for human immunodeficiency virus type 1 (HIV-1) p24 antigen would improve transfusion safety by identifying carriers of the virus who are seronegative for HIV-1 antibody.


METHODS
More than 500,000 donations were tested at 13 U.S. blood centers with test kits from two manufacturers. Units found repeatedly reactive were retested in a central laboratory; if the results were positive, they were confirmed by a neutralization assay. A subgroup of units was also tested for HIV-1 by the polymerase chain reaction. Selected donors confirmed or not confirmed as having p24 antigen were contacted for follow-up interviews to identify risk factors and undergo retesting for HIV-1 markers.


RESULTS
Positive tests for p24 antigen were confirmed by neutralization in five donors (0.001 percent of all donations tested), all of whom were also positive for HIV-1 antibody and HIV-1 by polymerase chain reaction. Three of the antigen-positive donors had other markers of infectious disease that would have resulted in the exclusion of their blood; two had risk factors for HIV-1 that should have led to self-exclusion. Of 220 blood units with repeatedly reactive p24 antigen whose presence could not be confirmed by neutralization (0.04 percent of the donations studied), none were positive for HIV-1 antibody, HIV-1 by polymerase chain reaction (120 units tested), or virus culture (76 units tested)--attesting to the specificity of confirmatory neutralization.


CONCLUSIONS
The finding that no donation studied was positive for p24 antigen and negative for HIV-1 antibody suggests that screening donors for p24 antigen with tests of the current level of sensitivity would not add substantially to the safety of the U.S. blood supply.
Alter
H J
HJ
National Institutes of Health, Bethesda, Md.
Epstein
J S
JS
Swenson
S G
SG
VanRaden
M J
MJ
Ward
J W
JW
Kaslow
R A
RA
Menitove
J E
JE
Klein
H G
HG
Sandler
S G
SG
Sayers
M H
MH
D001782:Blood Donors; D015683:Gene Products, gag / Q000032:analysis*; D015483:HIV Antibodies / Q000032:analysis; D015488:HIV Antigens / Q000032:analysis*; D016655:HIV Core Protein p24; D015528:HIV Seroprevalence; D015497:HIV-1 / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D009500:Neutralization Tests; D016133:Polymerase Chain Reaction; D014481:United States / Q000453:epidemiology; D014758:Viral Core Proteins / Q000032:analysis*
D015683:Gene Products, gag; D015483:HIV Antibodies; D015488:HIV Antigens; D016655:HIV Core Protein p24; D014758:Viral Core Proteins