Routine HIV screening among blood donors in Buenos Aires (Argentina): results from six years' experience and report of a single window-period donation.
BACKGROUND
Blood donor HIV antibody detection has been mandatory in Argentina since 1991, and p24 antigen screening was recommended in 1997.


METHODS
A total of 30,132 consecutive donations were screened. Repeatedly reactive samples were tested by another screening test and/or by Western blot (WB) for HIV Ab, or by a neutralization assay for p24 Ag.


RESULTS
Among the total, 0.3623% of samples were repeatedly reactive and 0.2084% were true HIV-infected donors. Only one donor tested nonreactive for HIV Ab, repeatedly reactive for p24 Ag, positive by neutralization assay, and seroconverted later. Samples with a signal-to-cutoff (S/CO) ratio >/= 3.00 on routine HIV Ab testing were 100.0% positive by WB and/or repeatedly reactive by the second test. In samples with a S/CO ratio < 3.00, 11.1% were positive by WB and/or the majority were nonreactive by the second test. Among HIV-infected donors, 89.5% possessed risk factors (which had been denied previously), 56.5% were repeatedly reactive by other screening procedures and 88.6% were coinfected with other blood-transmissible viruses.


CONCLUSIONS
When the EIA S/CO ratio is >/= 3.00, WB can be replaced by a second screening test. The pre-donation questionnaire should be improved to detect risk behavior in prospective donors. There was a high association between HIV and other blood-transmissible viruses.
Gendler
Silvina Alejandra
SA
Hemotherapy and Immunohematology Unit, Diagnosis and Treatment Department, Juan A. Fernández Hospital, Government of Buenos Aires City, Argentina. gendlersa@yahoo.com.ar
Pascuccio
María Susana
MS
D015492:AIDS Serodiagnosis / Q000379:methods / Q000706:statistics & numerical data; D000328:Adult; D000465:Algorithms; D001118:Argentina / Q000453:epidemiology; D001769:Blood / Q000382:microbiology / Q000821:virology; D001782:Blood Donors / Q000706:statistics & numerical data*; D017848:Blood-Borne Pathogens / Q000302:isolation & purification; D015153:Blotting, Western; D015897:Comorbidity; D004797:Enzyme-Linked Immunosorbent Assay; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D015483:HIV Antibodies / Q000097:blood; D016655:HIV Core Protein p24 / Q000097:blood; D015658:HIV Infections / Q000175:diagnosis / Q000453:epidemiology*; D006679:HIV Seropositivity; D015497:HIV-1 / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D015498:HIV-2 / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D009500:Neutralization Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors
D015483:HIV Antibodies; D016655:HIV Core Protein p24