Simple/rapid test devices for anti-HIV screening: Do they come up to the mark?

Field Evaluation of Four Rapid Tests for Diagnosis of HIV Infection in Panama

Four HIV rapid tests were subjected to field validation in Panama and compared to an enzyme-linked immunosorbent assay/Multispot-based testing algorithm. The sensitivities of Determine, Uni-Gold, SD Bioline, and INSTI were 99.8%. The specificities of Determine, SD-Bioline, and Uni-Gold were 100%, and the specificity of INSTI was 99.8%. On the basis of these data, we determined that these rapid tests can be used in an appropriate algorithm to diagnose HIV infection and are suitable for use in testing and counseling settings in Panama.

Use of rapid HIV antibody testing for controlling the HIV pandemic

The HIV pandemic continues to expand throughout Africa and southern Asia. Despite recent advances in therapy, the primary means of prevention continues to be the identification of infected patients through diagnostic testing, and the provision of counseling services to reduce HIV transmission. In order to facilitate the identification of infected patients, great strides have been made during the past 10 years towards the development of simple, rapid HIV antibody assays that require no specialized equipment, are relatively stable at ambient temperatures and can be easily performed by people who do not have a laboratory background. Evaluations of these assays have shown that when used in multiple assay algorithm strategies, they perform comparably with current laboratory-based methods. Effective global implementation of these tests will require a concerted effort from public and private health agencies, however, expanding the use of these assays can provide a significant opportunity to slow the devastating spread of HIV.

Rapid tests for detection of viral markers in blood transfusion

Since the early 1990s, rapid tests have been available for detection of HIV infection. They were intended for field diagnosis, emergency and home testing. In addition, rapid tests for anti-HIV, hepatitis B surface antigen and antihepatitis C virus have been used for blood screening in many resource-poor areas to save resources and overcome lack of funding, equipment and electrical supply. The performance of rapid tests varies widely but some have sensitivity and specificity levels that meet standards established by enzyme immunoassays for anti-HIV. Compared with genomic detection of hepatitis B virus, hepatitis B surface antigen rapid tests and enzyme immunoassays have insufficient sensitivity. The clinical consequences of this performance deficit remain to be clarified. Anti-hepatitis C virus rapid tests detect chronically infected individuals who are viremic, however, further studies are required to fully assess their performance. In settings where few blood donations are collected and equipment is unavailable, rapid tests provide a flexible, technically undemanding and relatively inexpensive approach to ensuring a safer blood supply. When utilized for predonation screening in areas of high endemicity of viral markers, rapid tests provide the means to limit blood bag wasting, store only clinically usable blood and inform and counsel deferred donors. As with any laboratory assay, adequate training and sustained quality assurance programs are critical to maintain a safe supply of blood. As a means of achieving a safe blood supply, rapid tests for viral markers and nucleic acid testing have a place next to classic enzyme immunoassays in the definition of strategies that are adapted to a setting's epidemiology, the size and type of donor base, equipment, staff training and resources.

Use of stored serum from Uganda for development and evaluation of a human immunodeficiency virus type 1 testing algorithm involving multiple rapid immunoassays

We report the development and evaluation of a human immunodeficiency virus type 1 testing algorithm consisting of three rapid antibody detection tests. Stored serum samples from Uganda were utilized with a final algorithm sensitivity of 100% and a specificity of 98.9% (95% confidence interval, 98.6% to 99.3%).

Evaluation of rapid HIV testing strategies in under equipped laboratories in the Central African Republic

Voluntary testing is described as being cornerstone to impact the spread of human immunodeficiency virus (HIV) infection if the person who tests positive is counseled. Therefore, simple, accurate and affordable diagnostic tests are required. The immunoblot test used in developed countries is too expensive for large-scale use in developing countries. Therefore, alternative strategies must be developed. A strategy based on two consecutive rapid tests was tested. This strategy used the Determine HIV-1/2 (Abbott Laboratories, Tokyo, Japan) rapid immunochromatographic test as a screening test and the Uni-Gold HIV test (Trinity Biotech, Dublin, Ireland), SDHO HIV 1/2 test (SDHO laboratories, Saint-Sauveur des Monts, Canada), HIV 1/2 Quick test (Cypress Diagnostics, Langdorp, Belgium) or Retrocheck HIV test (Qualpro Diagnostics, Goa, India) as a confirmatory test. Reference serum samples (HIV-positive and HIV-negative) were first used to evaluate the four confirmatory tests. Secondly, 159 serum samples were used to compare the "consecutive" testing strategy used in our laboratory with the two-test strategy. Thirdly, we tested the feasibility of using this two-test strategy in a under equipped laboratory. The sensitivity and negative predictive value of both test strategies were 100%. The specificity and positive predictive value of the four confirmatory tests were similar (>98%). The strategy used in our laboratory and the two-test strategy always gave identical results, regardless of where this strategy was performed (Institut Pasteur de Bangui or M'baïki hospital). This new strategy appears to be reliable, simple, feasible and rapid in under equipped laboratories. It allows counseling and results to be given on the same day, which should improve post-test counseling.

Use of rapid and conventional testing technologies for human immunodeficiency virus type 1 serologic screening in a rural Kenyan reference laboratory

We report a prospective comparison of human immunodeficiency virus type 1 testing by enzyme immunoassay and Western blot with four rapid tests of 486 subjects performed in rural Kenya. Rapid test sensitivity was 100%. Specificity ranged from 99.1 to 100%. Combined use of two Food and Drug Administration-approved rapid tests yielded a single false-positive result.

Field evaluation of a rapid human immunodeficiency virus (HIV) serial serologic testing algorithm for diagnosis and differentiation of HIV type 1 (HIV-1), HIV-2, and dual HIV-1-HIV-2 infections in West African pregnant women

We evaluated a two-rapid-test serial algorithm using the Determine and Genie II rapid assays, performed on-site in four peripheral laboratories during the French Agence Nationale de Recherches sur le SIDA (ANRS) 1201/1202 Ditrame Plus cohort developed for prevention of mother-to-child transmission of human immunodeficiency virus (HIV) infection in Côte d'Ivoire. A total of 1,039 specimens were retested by two commercial enzyme-linked immunosorbent assays (ELISAs). The following specimens were tested: 315 specimens found on-site to be infected with HIV type 1 (HIV-1), 8 specimens found on-site to be infected with HIV-2, 71 specimens found on-site to be infected with both HIV-1 and HIV-2, 40 specimens found on-site to have indeterminate results for HIV infection, and 605 specimens taken during a quality assurance program. For HIV discrimination, 99 positive serum samples (20 with HIV-1, 8 with HIV-2, and 71 with HIV-1 and HIV-2 on the basis of our rapid test algorithm) were retested by the Peptilav test, Western blot (WB) assays, and homemade monospecific ELISAs. Real-time DNA PCRs for the detection of HIV-1 and HIV-2 were performed with peripheral blood mononuclear cells from 35 women diagnosed on-site with HIV-1 and HIV-2 infections. Compared to the results of the ELISAs, the sensitivities of the Determine and Genie II assays were 100% (95% lower limit [95% LL], 99.1%) and 99.5% (95% confidence interval [95% CI], 98.2 to 99.9%), respectively. The specificities were 98.4% (95% CI, 96.9 to 99.3%) and 100% (95% LL, 99.3%), respectively. All serological assays gave concordant results for infections with single types. By contrast, for samples found to be infected with dual HIV types by the Genie II assay, dual reactivity was detected for only 37 samples (52.1%) by WB assays, 34 samples (47.9%) by the Peptilav assay, and 23 samples (32.4%) by the monospecific ELISAs. For specimens with dual reactivity by the Genie II assay, the rates of concordance between the real-time PCR assays and the serological assays were 25.7% for the Genie II assay, 82.9% for the Peptilav assay, 74.3% for WB assays, and 80% for the homemade ELISAs. Our algorithm provided high degrees of sensitivity and specificity comparable to those of ELISAs. Even if they are rare, women identified by the Genie II assay as being infected with HIV-1 and HIV-2 mostly appeared to be infected only with HIV-2.

Performance of the OraQuick rapid antibody test for diagnosis of human immunodeficiency virus type 1 infection in patients with various levels of exposure to highly active antiretroviral therapy

With oral mucosal transudate and serum samples from 101 human immunodeficiency virus type 1 (HIV-1)-infected subjects and 100 HIV-1-negative volunteers, the OraQuick HIV-1 test demonstrated 100% specificity and 96% sensitivity. Four false-negative subjects, who were characterized by early initiation of effective antiretroviral therapy, demonstrated waning serum anti-gp41 titers and Western blot band intensities.

Preventing mother-to-child transmission of HIV in developing countries: recent developments and ethical implications

Various regimens of antiretroviral (ARV) therapy during pregnancy and labour have been found to be effective in reducing the risk of mother-to-child transmission of HIV. Cost and late identification of women with HIV infection during pregnancy in many developing countries have been the impetus to study inexpensive, short-course ARV regimens. Recently, it was shown that a single dose of nevirapine given orally once during labour to the mother and once to the infant greatly reduces the risk of HIV transmission. As a result, it has been proposed that in high HIV prevalence areas, this drug regimen be offered routinely to all pregnant women and their infants, without the need for an HIV test. This is seen as a cost-effective alternative to trying to make voluntary HIV testing and counselling universally available to pregnant women, which would require improved antenatal uptake and care, high uptake of HIV testing and high rates of return to learn results before women could make decisions regarding ARV prophylaxis. The ethical dilemmas arising from both these options are currently under debate, against a backdrop of concerns about breastfeeding and breastmilk substitutes, what to do about the increasing numbers of AIDS orphans and how to prevent HIV transmission to women in the first place.