HIV Rapid Diagnostic Tests Research Articles

Photographed Rapid HIV Test Results Pilot Novel Quality Assessment and Training Schemes

HIV rapid diagnostic tests (RDTs) are now used widely in non-laboratory settings by non-laboratory-trained operators. Quality assurance programmes are essential in ensuring the quality of HIV RDT outcomes. However, there is no cost-effective means of supplying the many operators of RDTs with suitable quality assurance schemes. Therefore, it was examined whether photograph-based RDT results could be used and correctly interpreted in the non-laboratory setting. Further it was investigated if a single training session improved the interpretation skills of RDT operators. The photographs were interpreted, a 10-minute tutorial given and then a second interpretation session was held. It was established that the results could be read with accuracy. The participants (n = 75) with a range of skills interpreted results (>80% concordance with reference results) from a panel of 10 samples (three negative and seven positive) using four RDTs. Differences in accuracy of interpretation before and after the tutorial were marked in some cases. Training was more effective for improving the accurate interpretation of more complex results, e.g. results with faint test lines or for multiple test lines, and especially for improving interpretation skills of inexperienced participants. It was demonstrated that interpretation of RDTs was improved using photographed results allied to a 10-minute training session. It is anticipated that this method could be used for training but also for quality assessment of RDT operators without access to conventional quality assurance or training schemes requiring wet samples.

The Evaluation of a Rapid In Situ HIV Confirmation Test in a Programme with a High Failure Rate of the WHO HIV Two-Test Diagnostic Algorithm

BackgroundConcerns about false-positive HIV results led to a review of testing procedures used in a Médecins Sans Frontières (MSF) HIV programme in Bukavu, eastern Democratic Republic of Congo. In addition to the WHO HIV rapid diagnostic test algorithm (RDT) (two positive RDTs alone for HIV diagnosis) used in voluntary counselling and testing (VCT) sites we evaluated in situ a practical field-based confirmation test against western blot WB. In addition, we aimed to determine the false-positive rate of the WHO two-test algorithm compared with our adapted protocol including confirmation testing, and whether weakly reactive compared with strongly reactive rapid test results were more likely to be false positives.Methodology/Principal Findings2864 clients presenting to MSF VCT centres in Bukavu during January to May 2006 were tested using Determine HIV-1/2® and UniGold HIV® rapid tests in parallel by nurse counsellors. Plasma samples on 229 clients confirmed as double RDT positive by laboratory retesting were further tested using both WB and the Orgenics Immunocomb Combfirm® HIV confirmation test (OIC-HIV). Of these, 24 samples were negative or indeterminate by WB representing a false-positive rate of the WHO two-test algorithm of 10.5% (95%CI 6.6-15.2). 17 of the 229 samples were weakly positive on rapid testing and all were negative or indeterminate by WB. The false-positive rate fell to 3.3% (95%CI 1.3–6.7) when only strong-positive rapid test results were considered. Agreement between OIC-HIV and WB was 99.1% (95%CI 96.9–99.9%) with no false OIC-HIV positives if stringent criteria for positive OIC-HIV diagnoses were used.ConclusionsThe WHO HIV two-test diagnostic algorithm produced an unacceptably high level of false-positive diagnoses in our setting, especially if results were weakly positive. The most probable causes of the false-positive results were serological cross-reactivity or non-specific immune reactivity. Our findings show that the OIC-HIV confirmation test is practical and effective in field contexts. We propose that all double-positive HIV RDT samples should undergo further testing to confirm HIV seropositivity until the accuracy of the RDT testing algorithm has been established at programme level.

O desafio da prevenção da transmissão vertical do HIV no Município de Campos dos Goytacazes, Rio de Janeiro, Brasil

Prevention of mother-to-child HIV transmission is an emerging public health challenge. In Brazil, preventive prophylaxis with AZT during pregnancy, at delivery, and for newborns was introduced in 1996, with a marked reduction in transmission (less than 5.0% nationwide). Since 1999 the Municipal STD/AIDS Program in Campos dos Goytacazes, Rio de Janeiro State (population = 416,441) has acted in the prevention of vertical transmission. In 2001/2003, there was a moderately increased implementation (from 28.0% to 36.0%) of HIV screening services during pregnancy, and more pregnant women were knowledgeable about vertical HIV transmission. Remaining challenges are to expand HIV screening to pregnant women at large and to effectively introduce rapid diagnostic tests for HIV in the delivery room. Such actions are expected to change the current situation, in which only 6.8% of infected children under observation had access to prophylaxis for vertical HIV transmission.

Determinantes de la transmisión vertical del VIH en Cataluña (1997-2001): ¿es posible su eliminación?

ObjectivesTo identify and describe the factors that have led to new cases of HIV infection through mother-to-child transmission since the introduction of antiretroviral therapy in HIVseropositive pregnant women (1997-2001) in Catalonia. MethodsSystematic review of cases identified in the pediatric services of all the hospitals in Catalonia. ResultsTwenty-eight cases of pediatric HIV infection were identified: 9, 9, 8, 2 and 0 per year of birth from 1997 to 2001, respectively. Of 16 mothers with a diagnosis of known HIV infection before or during pregnancy, nine underwent antiretroviral prophylaxis during pregnancy (compliance was good in five, unknown in one and poor in one) and seven did not undergo prophylaxis (six refused it and no information was available in one). Of 12 mothers diagnosed after delivery, pregnancy was not monitored in five and was little or well-monitored in the remaining seven. Of mothers with well-monitored pregnancy, a serological HIV test was not performed in six and was negative in the first trimester in one. ConclusionsMother-to-child transmission of HIV has decreased in the last few years in Catalonia, but infections have sometimes occurred through poor implementation of preventive measures. Pregnant women should be offered an HIV diagnostic test not only in the first trimester but also at the end of pregnancy if HIV exposure is suspected. In women with unmonitored pregnancies, rapid diagnostic tests for HIV should be used in the delivery room.