Detection of HIV-1 and HCV infections among antibody-negative blood donors by nucleic acid-amplification testing.
BACKGROUND
Testing of blood donors for human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) RNA by means of nucleic acid amplification was introduced in the United States as an investigational screening test in mid-1999 to identify donations made during the window period before seroconversion.


METHODS
We analyzed all antibody-nonreactive donations that were confirmed to be positive for HIV-1 and HCV RNA on nucleic acid-amplification testing of "minipools" (pools of 16 to 24 donations) by the main blood-collection programs in the United States during the first three years of nucleic acid screening.


RESULTS
Among 37,164,054 units screened, 12 were confirmed to be positive for HIV-1 RNA--or 1 in 3.1 million donations--only 2 of which were detected by HIV-1 p24 antigen testing. For HCV, of 39,721,404 units screened, 170 were confirmed to be positive for HCV RNA, or 1 in 230,000 donations (or 1 in 270,000 on the basis of 139 donations confirmed to be positive for HCV RNA with the use of a more sensitive HCV-antibody test). The respective rates of positive HCV and HIV-1 nucleic acid-amplification tests were 3.3 and 4.1 times as high among first-time donors as among donors who gave blood repeatedly. Follow-up studies of 67 HCV RNA-positive donors demonstrated that seroconversion occurred a median of 35 days after the index donation, followed by a low rate of resolution of viremia; three cases of long-term immunologically silent HCV infection were documented.


CONCLUSIONS
Minipool nucleic acid-amplification testing has helped prevent the transmission of approximately 5 HIV-1 infections and 56 HCV infections annually and has reduced the residual risk of transfusion-transmitted HIV-1 and HCV to approximately 1 in 2 million blood units.
Stramer
Susan L
SL
American Red Cross, Gaithersburg, Md, USA. stramers@usa.redcross.org
Glynn
Simone A
SA
Kleinman
Steven H
SH
Strong
D Michael
DM
Caglioti
Sally
S
Wright
David J
DJ
Dodd
Roger Y
RY
Busch
Michael P
MP
D000410:Alanine Transaminase / Q000097:blood; D001782:Blood Donors; D015483:HIV Antibodies / Q000097:blood; D015658:HIV Infections / Q000097:blood / Q000175:diagnosis* / Q000635:transmission; D015497:HIV-1 / Q000302:isolation & purification*; D016174:Hepacivirus / Q000302:isolation & purification*; D006526:Hepatitis C / Q000097:blood / Q000175:diagnosis* / Q000635:transmission; D018937:Hepatitis C Antibodies / Q000097:blood; D006801:Humans; D021141:Nucleic Acid Amplification Techniques; D012367:RNA, Viral / Q000032:analysis; D014766:Viremia / Q000175:diagnosis*
D015483:HIV Antibodies; D018937:Hepatitis C Antibodies; D012367:RNA, Viral; D000410:Alanine Transaminase