Clinic-based evaluation of point-of-care dual HIV/syphilis rapid diagnostic tests at primary healthcare antenatal facilities in South Africa and Zambia.

BACKGROUND: Southern African countries have the largest global burden of HIV and syphilis, with a high prevalence among women of reproductive age. Although antenatal screening is standard of care, syphilis screening has generally lagged behind HIV screening. We aimed to evaluate the performance and operational characteristics of two commercial dual HIV/syphilis point-of-care tests (POCTs) for simultaneous maternal HIV/syphilis screening. METHODS: A clinic-based evaluation of dual HIV/syphilis POCTs (SD Bioline and Chembio) was conducted at five primary healthcare centres (PHCs) in South Africa and Zambia. POCT results using capillary fingerprick blood were compared to reference laboratory syphilis and HIV serological assays. RESULTS: Three thousand four hundred twelve consenting pregnant women aged ≥ 18 years were enrolled. The prevalence of treponemal antibody seropositivity and HIV infection ranged from 3.7 to 9.9% (n = 253) and 17.8 to 21.3% (n = 643), respectively. Pooled sensitivity for syphilis compared to the reference assay was 66.0% (95%CI 57.7-73.4) with SD Bioline and 67.9% (95%CI 58.2-76.3) with Chembio. Pooled specificity for syphilis was above 98% with both POCTs. The sensitivities of SD Bioline and Chembio assays were 78.0% (95%CI 68.6-85.7) and 81.0% (95%CI 71.9-88.2), respectively compared to an active syphilis case definition of treponemal test positive with a rapid plasma reagin titre of ≥ 8. The negative predictive values (NPVs) based on various prevalence estimates for syphilis with both assays ranged from 97 to 99%. The pooled sensitivity for HIV was 92.1% (95%CI 89.4-94.2) with SD Bioline; and 91.5% (95%CI 88.2-93.9) with Chembio. The pooled specificities for HIV were 97.2% (95%CI 94.8-98.5) with SD Bioline and 96.7% (95%CI 95.1-97.8) with Chembio. The NPV based on various prevalence estimates for HIV with both assays was approximately 98%. Most participating women (91%) preferred dual POCTs over two single POCTs for HIV and syphilis, and healthcare providers gave favourable feedback on the utility of both assays at PHC level. CONCLUSIONS: Based on the need to improve antenatal screening coverage for syphilis, dual HIV/syphilis POCTs could be effectively incorporated into antenatal testing algorithms to enhance efforts towards elimination of mother-to-child transmission of these infections.

Field performance evaluation of dual rapid HIV and syphilis tests in three antenatal care clinics in Zambia.

This cross-sectional study of 3212 pregnant women assessed the field performance, acceptability, and feasibility of two dual HIV/syphilis rapid diagnostic tests, the Chembio DPP HIV-syphilis Assay and the SD Bioline HIV/syphilis Duo in antenatal clinics. Sensitivity and specificity for HIV and syphilis were calculated compared to the rapid Determine HIV-1/2 with Uni-Gold to confirm positive results for HIV and the Treponema pallidum particle agglutination assay for syphilis. RPR titers ≥1:4 were used to define active syphilis detection. Acceptability and feasibility were assessed using self-reported questionnaires. For Chembio, the HIV sensitivity was 90.6% (95%CI = 87.4, 93.0) and specificity was 97.2% (95%CI = 96.2, 97.8); syphilis sensitivity was 68.6% (95%CI = 61.9, 74.6) and specificity was 98.5% (95%CI = 97.8, 98.9). For SD Bioline, HIV sensitivity was 89.4% (95%CI = 86.1, 92.0) and specificity was 96.3% (95%CI = 95.3, 97.1); syphilis sensitivity was 66.2% (95%CI = 59.4, 72.4) and specificity was 97.2% (95%CI = 96.4, 97.9). Using the reference for active syphilis, syphilis sensitivity was 84.7% (95%CI = 76.1, 90.6) for Chembio and 81.6% (95%CI = 72.7, 88.1) for SD Bioline. Both rapid diagnostic tests were assessed as highly acceptable and feasible. In a field setting, the performance of both rapid diagnostic tests was comparable to other published field evaluations and each was rated highly acceptable and feasible. These findings can be used to guide further research and proposed scale up in antenatal clinic settings.

Clinic-based evaluation study of the diagnostic accuracy of a dual rapid test for the screening of HIV and syphilis in pregnant women in Nigeria.

BACKGROUND: Screening pregnant women for HIV and syphilis is recommended by WHO in order to reduce mother-to-child transmission. We evaluated the field performance, feasibility, and acceptability of a dual rapid diagnostic test (RDT) for HIV and syphilis test in antenatal clinic settings in Nigeria. METHODS AND FINDINGS: Participants were recruited at 12 antenatal clinic sites in three states of Nigeria. All consenting individuals were tested according to the national HIV testing algorithm, as well as a dual RDT, the SD BIOLINE HIV/Syphilis Duo Test (Alere, USA), in the clinic. To determine sensitivity, specificity and concordance, whole blood samples were obtained for repeat RDT performance in the laboratory, as well as reference tests for HIV and syphilis. Dual test acceptability and operational characteristics were assessed among participants and clinic staff. The prevalence of HIV among the 4,551 enrollees was 3.0% (138/4551) using the national clinic-based HIV testing algorithm. Positive and negative percent agreement of the HIV component of the dual RDT were 100.0% (95% CI 99.7-100.0) and 99.9% (95% CI 99.7-100.0) respectively, when compared with the national rapid testing algorithm. The prevalence of syphilis, using TPHA as the reference test, was low at 0.09% (4/4550). The sensitivity of the syphilis component of the dual RDT could not be calculated as no positive results were observed for patients that were positive for syphilis by TPHA. Each of the only four TPHA-positive specimens had RPR titers of 1:1 (neat), indicative of non-active syphilis. The specificity of the syphilis component of the dual RDT was 99.9% (95% CI 99.8-100.0). The dual RDT received favorable feasibility ratings among antenatal care clinic staff. Acceptability among study participants was high with most women reporting preference for rapid dual HIV/syphilis testing. CONCLUSIONS: The SD BIOLINE HIV/Syphilis Duo Test showed a high overall diagnostic accuracy for HIV and a high specificity for syphilis diagnosis in antenatal clinic settings. This study adds to a growing body of evidence that supports the clinic-based use of dual tests for HIV and syphilis among pregnant women.

Elimination of mother-to-child transmission of HIV and Syphilis (EMTCT): Process, progress, and program integration.

Melanie Taylor and colleagues discuss progress towards eliminating vertical transmission of HIV and syphilis.

A comparative analysis of costs of single and dual rapid HIV and syphilis diagnostics: results from a randomised controlled trial in Colombia.

BACKGROUND: HIV and congenital syphilis are major public health burdens contributing to substantial perinatal morbidity and mortality globally. Although studies have reported on the costs and cost-effectiveness of rapid diagnostic tests (RDTs) for syphilis screening within antenatal care in a number of resource-constrained settings, empirical evidence on country-specific cost and estimates of single RDTs compared with dual RDTs for HIV and syphilis are limited. METHODS: A cluster randomised controlled study design was used to compare the incremental costs of two testing algorithms: (1) single RDTs for HIV and syphilis and (2) dual RDTs for HIV and syphilis, in 12 health facilities in Bogota and Cali, Colombia. The costs of single HIV and syphilis RDTs and dual HIV and syphilis RDTs were collected from each of the health facilities. The economic costs per woman tested for HIV and syphilis and costs per woman treated for syphilis defined as the total costs required to test and treat one woman for syphilis were estimated. RESULTS: A total of 2214 women were tested in the study facilities. Cost per pregnant woman tested and cost per woman treated for syphilis were US$10.26 and US$607.99, respectively in the single RDT arm. For the dual RDTs, the cost per pregnant woman tested for HIV and syphilis and cost per woman treated for syphilis were US$15.89 and US$1859.26, respectively. Overall costs per woman tested for HIV and syphilis and cost per woman treated for syphilis were lower in Cali compared with Bogota across both intervention arms. Staff costs accounted for the largest proportion of costs while treatment costs comprised <1% of the preventive programme. CONCLUSIONS: Findings show lower average costs for single RDTs compared with dual RDTs with costs sensitive to personnel costs and the scale of output at the health facilities. TRIAL REGISTRATION NUMBER: NCT02454816; results.

Comparative effectiveness of single and dual rapid diagnostic tests for syphilis and HIV in antenatal care services in Colombia / Comparación de la eficacia de la prueba rápida individual y la prueba rápida dual para el diagnóstico de la sífilis y la infección por el VIH en los servicios de atención prenatal en Colombia

Objective. To assess the effectiveness of a dual rapid test compared to a single rapid test for syphilis and HIV screening. Methods. A cluster-randomized open-label clinical trial was performed in 12 public antenatal care (ANC) centers in the cities of Bogotá and Cali, Colombia. Pregnant women who were over 14 years of age at their first antenatal visit and who had not been previously tested for HIV and syphilis during the current pregnancy were included. Pregnant women were randomized to single HIV and single syphilis rapid diagnostic tests (Arm A) or to dual HIV and syphilis rapid diagnostic tests (Arm B). The four main outcomes measured were: (1) acceptability of the test, (2) uptake in testing, (3) treatment on the same day (that is, timely treatment), and (4) treatment at any time for positive rapid test cases. Bivariate and multivariate analyses were calculated to adjust for the clustering effect and the period. Results. A total of 1 048 patients were analyzed in Arm A, and 1 166 in Arm B. Acceptability of the rapid tests was 99.8% in Arm A and 99.6% in Arm B. The prevalence of positive rapid tests was 2.21% for syphilis and 0.36% for HIV. Timely treatment was provided to 20 of 29 patients (69%) in Arm A and 16 of 20 patients (80%) in Arm B (relative risk (RR), 1.10; 95% confidence interval (CI): (1.00 −1.20). Treatment at any time was given to 24 of 29 patients (83%) in Arm A and to 20 of 20 (100%) in Arm B (RR, 1.11; 95% CI: 1.01−1.22). Conclusions. There were no differences in patient acceptability, testing and timely treatment between dual rapid tests and single rapid tests for HIV and syphilis screening in the ANC centers. Same-day treatment depends also on the interpretation of and confidence in the results by the health providers.

Objetivo. Evaluar la eficacia de la prueba rápida dual en comparación con la prueba rápida individual para la detección sistemática de la sífilis y la infección por el VIH. Métodos. Se realizó un ensayo clínico sin enmascaramiento y aleatorizado por grupos en 12 centros públicos de atención prenatal en las ciudades de Bogotá y Cali (Colombia). Se incluyó a las mujeres embarazadas de 14 o más años de edad que asistían a su primera consulta prenatal y no se habían realizado pruebas en este embarazo. Las embarazadas se dividieron de forma aleatoria para realizarles las pruebas rápidas individuales para el diagnóstico de sífilis y de infección por el VIH (Grupo A) o la prueba rápida dual para el diagnóstico de la sífilis y la infección por el VIH (Grupo B). Se midieron principalmente cuatro resultados: (1) aceptabilidad de la prueba, (2) uso de los servicios de prueba, (3) tratamiento el mismo día (es decir, tratamiento oportuno) y (4) tratamiento en cualquier momento en los casos con resultados positivos en las pruebas rápidas. Se realizaron análisis bifactoriales y multifactoriales para hacer los ajustes pertinentes por el efecto de la división en grupos y el período. Resultados. Se estudió a 1 048 pacientes en el Grupo A y a 1 166 en el Grupo B. La aceptabilidad de las pruebas rápidas fue de 99,8% en el Grupo A y 99,6% en el Grupo B. La prevalencia de resultados positivos en las pruebas rápidas fue de 2,21% para la sífilis y 0,36% para la infección por el VIH. Se administró tratamiento oportuno a 20 de 29 pacientes (69%) del Grupo A y a 16 de 20 pacientes (80%) del Grupo B (riesgo relativo, 1,10; intervalo de confianza de 95% (IC): 1,00-1,20). Se administró tratamiento en cualquier momento a 24 de 29 pacientes (83%) del Grupo A y a 20 de 20 (100%) del Grupo B (riesgo relativo, 1,11; IC de 95%: 1,01-1,22). Conclusiones. No hubo diferencias en cuanto a la aceptabilidad por parte de los pacientes, y el uso de los servicios de cribaje y el tratamiento oportuno entre las pruebas rápidas duales y las pruebas rápidas individuales para la detección sistemática de la sífilis y la infección por el VIH en los centros de atención prenatal. El tratamiento el mismo día depende también de la interpretación y la confianza en los resultados del trabajador de salud.

Comparative effectiveness of single and dual rapid diagnostic tests for syphilis and HIV in antenatal care services in Colombia / Comparación de la eficacia de la prueba rápida individual y la prueba rápida dual para el diagnóstico de la sífilis y la infección por el VIH en los servicios de atención prenatal en Colombia

ABSTRACT Objective To assess the effectiveness of a dual rapid test compared to a single rapid test for syphilis and HIV screening. Methods A cluster-randomized open-label clinical trial was performed in 12 public antenatal care (ANC) centers in the cities of Bogotá and Cali, Colombia. Pregnant women who were over 14 years of age at their first antenatal visit and who had not been previously tested for HIV and syphilis during the current pregnancy were included. Pregnant women were randomized to single HIV and single syphilis rapid diagnostic tests (Arm A) or to dual HIV and syphilis rapid diagnostic tests (Arm B). The four main outcomes measured were: (1) acceptability of the test, (2) uptake in testing, (3) treatment on the same day (that is, timely treatment), and (4) treatment at any time for positive rapid test cases. Bivariate and multivariate analyses were calculated to adjust for the clustering effect and the period. Results A total of 1 048 patients were analyzed in Arm A, and 1 166 in Arm B. Acceptability of the rapid tests was 99.8% in Arm A and 99.6% in Arm B. The prevalence of positive rapid tests was 2.21% for syphilis and 0.36% for HIV. Timely treatment was provided to 20 of 29 patients (69%) in Arm A and 16 of 20 patients (80%) in Arm B (relative risk (RR), 1.10; 95% confidence interval (CI): (1.00 −1.20). Treatment at any time was given to 24 of 29 patients (83%) in Arm A and to 20 of 20 (100%) in Arm B (RR, 1.11; 95% CI: 1.01−1.22). Conclusions There were no differences in patient acceptability, testing and timely treatment between dual rapid tests and single rapid tests for HIV and syphilis screening in the ANC centers. Same-day treatment depends also on the interpretation of and confidence in the results by the health providers.

RESUMEN Objetivo Evaluar la eficacia de la prueba rápida dual en comparación con la prueba rápida individual para la detección sistemática de la sífilis y la infección por el VIH. Métodos Se realizó un ensayo clínico sin enmascaramiento y aleatorizado por grupos en 12 centros públicos de atención prenatal en las ciudades de Bogotá y Cali (Colombia). Se incluyó a las mujeres embarazadas de 14 o más años de edad que asistían a su primera consulta prenatal y no se habían realizado pruebas en este embarazo. Las embarazadas se dividieron de forma aleatoria para realizarles las pruebas rápidas individuales para el diagnóstico de sífilis y de infección por el VIH (Grupo A) o la prueba rápida dual para el diagnóstico de la sífilis y la infección por el VIH (Grupo B). Se midieron principalmente cuatro resultados: (1) aceptabilidad de la prueba, (2) uso de los servicios de prueba, (3) tratamiento el mismo día (es decir, tratamiento oportuno) y (4) tratamiento en cualquier momento en los casos con resultados positivos en las pruebas rápidas. Se realizaron análisis bifactoriales y multifactoriales para hacer los ajustes pertinentes por el efecto de la división en grupos y el período. Resultados Se estudió a 1 048 pacientes en el Grupo A y a 1 166 en el Grupo B. La aceptabilidad de las pruebas rápidas fue de 99,8% en el Grupo A y 99,6% en el Grupo B. La prevalencia de resultados positivos en las pruebas rápidas fue de 2,21% para la sífilis y 0,36% para la infección por el VIH. Se administró tratamiento oportuno a 20 de 29 pacientes (69%) del Grupo A y a 16 de 20 pacientes (80%) del Grupo B (riesgo relativo, 1,10; intervalo de confianza de 95% (IC): 1,00-1,20). Se administró tratamiento en cualquier momento a 24 de 29 pacientes (83%) del Grupo A y a 20 de 20 (100%) del Grupo B (riesgo relativo, 1,11; IC de 95%: 1,01-1,22). Conclusiones No hubo diferencias en cuanto a la aceptabilidad por parte de los pacientes, y el uso de los servicios de cribaje y el tratamiento oportuno entre las pruebas rápidas duales y las pruebas rápidas individuales para la detección sistemática de la sífilis y la infección por el VIH en los centros de atención prenatal. El tratamiento el mismo día depende también de la interpretación y la confianza en los resultados del trabajador de salud.

Comparative effectiveness of single and dual rapid diagnostic tests for syphilis and HIV in antenatal care services in Colombia.

OBJECTIVE: To assess the effectiveness of a dual rapid test compared to a single rapid test for syphilis and HIV screening. METHODS: A cluster-randomized open-label clinical trial was performed in 12 public antenatal care (ANC) centers in the cities of Bogotá and Cali, Colombia. Pregnant women who were over 14 years of age at their first antenatal visit and who had not been previously tested for HIV and syphilis during the current pregnancy were included. Pregnant women were randomized to single HIV and single syphilis rapid diagnostic tests (Arm A) or to dual HIV and syphilis rapid diagnostic tests (Arm B). The four main outcomes measured were: (1) acceptability of the test, (2) uptake in testing, (3) treatment on the same day (that is, timely treatment), and (4) treatment at any time for positive rapid test cases. Bivariate and multivariate analyses were calculated to adjust for the clustering effect and the period. RESULTS: A total of 1 048 patients were analyzed in Arm A, and 1 166 in Arm B. Acceptability of the rapid tests was 99.8% in Arm A and 99.6% in Arm B. The prevalence of positive rapid tests was 2.21% for syphilis and 0.36% for HIV. Timely treatment was provided to 20 of 29 patients (69%) in Arm A and 16 of 20 patients (80%) in Arm B (relative risk (RR), 1.10; 95% confidence interval (CI): (1.00 -1.20). Treatment at any time was given to 24 of 29 patients (83%) in Arm A and to 20 of 20 (100%) in Arm B (RR, 1.11; 95% CI: 1.01-1.22). CONCLUSIONS: There were no differences in patient acceptability, testing and timely treatment between dual rapid tests and single rapid tests for HIV and syphilis screening in the ANC centers. Same-day treatment depends also on the interpretation of and confidence in the results by the health providers.

Design aspects of a case-control clinical investigation of the effect of HIV on oral and gastrointestinal soluble innate factors and microbes.

INTRODUCTION: The impaired host defense system in HIV infection impacts the oral and gastrointestinal microbiota and associated opportunistic infections. Antiretroviral treatment is predicted to partially restore host defenses and decrease the oral manifestation of HIV/AIDS. Well-designed longitudinal studies are needed to better understand the interactions of soluble host defense proteins with bacteria and virus in HIV/AIDS. "Crosstalk" was designed as a longitudinal study of host responses along the gastrointestinal (GI) tract and interactions between defense molecules and bacteria in HIV infection and subsequent therapy. PURPOSE: The clinical core formed the infrastructure for the study of the interactions between the proteome, microbiome and innate immune system. The core recruited and retained study subjects, scheduled visits, obtained demographic and medical data, assessed oral health status, collected samples, and guided analysis of the hypotheses. This manuscript presents a well-designed clinical core that may serve as a model for studies that combine clinical and laboratory data. METHODS: Crosstalk was a case-control longitudinal clinical study an initial planned enrollment of 170 subjects. HIV+ antiretroviral naïve subjects were followed for 9 visits over 96 weeks and HIV uninfected subjects for 3 visits over 24 weeks. Clinical prevalence of oral mucosal lesions, dental caries and periodontal disease were assessed. RESULTS: During the study, 116 subjects (47 HIV+, 69 HIV-) were enrolled. Cohorts of HIV+ and HIV- were demographically similar except for a larger proportion of women in the HIV- group. The most prevalent oral mucosal lesions were oral candidiasis and hairy leukoplakia in the HIV+ group. DISCUSSION: The clinical core was essential to enable the links between clinical and laboratory data. The study aims to determine specific differences between oral and GI tissues that account for unique patterns of opportunistic infections and to delineate the differences in their susceptibility to infection by HIV and their responses post-HAART.

Early detection of HIV infection among Kenyan infants using a reverse transcriptase activity assay.

Two hundred HIV-exposed Kenyan infants were tested for HIV infection at birth and at age 6, 12, 24 and 48 weeks, by DNA polymerase chain reaction (PCR) and Cavidi reverse transcriptase (RT) assays and after age 18 months by HIV antibody test. Eleven (5.5%) infants became HIV infected. In 6 infants, positive RT preceded positive DNA PCR. The use of RT assay may facilitate earlier HIV diagnosis in infants.

Sex differences in the incidence of peripheral neuropathy among Kenyans initiating antiretroviral therapy.

BACKGROUND: Peripheral neuropathy (PN) is common among patients receiving antiretroviral therapy (ART) in resource-limited settings. We report the incidence of and risk factors for PN among human immunodeficiency virus (HIV)-infected Kenyan adults initiating ART. METHODS: An inception cohort was formed of adults initiating ART. They were screened for PN at baseline and every 3 months for 1 year. We used the validated Brief Peripheral Neuropathy Screen (BPNS) that includes symptoms and signs (vibration perception and ankle reflexes) of PN. RESULTS: Twenty-two (11%) of 199 patients had PN at baseline screening. One hundred fifty patients without evidence of PN at baseline were followed for a median of 366 days (interquartile range, 351-399). The incidence of PN was 11.9 per 100 person-years (95% confidence interval [CI], 6.9-19.1) and was higher in women than men (17.7 vs 1.9 per 100 person-years; rate ratio, 9.6; 95% CI, 1.27-72, P = .03). In stratified analyses, female sex remained statistically significant after adjustment for each of the following variables: age, CD4 cell count, body mass index, ART regimen, and tuberculosis treatment. Stratifying hemoglobin levels decreased the hazard ratio from 9.6 to 7.40 (P = .05), with higher levels corresponding to a lower risk of PN. CONCLUSIONS: HIV-infected Kenyan women were almost 10 times more likely than men to develop PN in the first year of ART. The risk decreased slightly at higher hemoglobin levels. Preventing or treating anemia in women before ART initiation and implementing BPNS during the first year of ART, the period of highest risk, could ameliorate the risk of PN.

Implementation of a validated peripheral neuropathy screening tool in patients receiving antiretroviral therapy in Mombasa, Kenya.

Limited objective data are available for the prevalence of peripheral neuropathy (PN) among antiretroviral (ART)-treated human immunodeficiency virus (HIV)-infected patients in resource-limited settings. A validated neuropathy-screening tool was integrated into routine ART visits at an HIV clinic in Mombasa, Kenya. Diagnosis of PN required at least one symptom and either abnormal vibratory sensation or deep tendon reflex bilaterally. Among 102 consecutively screened patients, 63% were women, 62% were receiving ART for < or = 1 year, and 86% were receiving a stavudine (D4T)-based regimen. Thirty-seven (36%) had PN. Univariate analysis showed that current D4T use was protective against PN (P = 0.03) and older age was a marginal risk factor (P = 0.05). Multivariate analysis showed that older age was a risk factor for neuropathy (P = 0.04). Peripheral neuropathy was common, particularly among older HIV-infected adults in Kenya. The protective association with current D4T use likely represents survivor effect bias. Longitudinal studies using this screen will help further characterize PN in resource-limited settings.

Monitoring virologic responses to antiretroviral therapy in HIV-infected adults in Kenya: evaluation of a low-cost viral load assay.

BACKGROUND: A key advantage of monitoring HIV viral load (VL) in persons receiving antiretroviral therapy (ART) is the ability to detect virologic failure before clinical deterioration or resistance occurs. Detection of virologic failure will help clarify the need for enhanced adherence counseling or a change to second- line therapy. Low-cost, locally performable alternates to expensive VL assays are needed where resources are limited. METHODOLOGY/PRINCIPAL FINDINGS: We monitored the response to 48-week ART in 100 treatment-naïve Kenyan adults using a low-cost VL measurement, the Cavidi reverse transcriptase (RT) assay and gold-standard assays, Roche RNA PCR and Bayer Versant HIV-1 RNA (bDNA) assays. In Altman-Bland plots, the mean difference in viral loads between the three assays was small (<0.5 log(10) copies/mL). However, the limits of agreement between the methods exceeded the biologically relevant change of 0.5 log copies/ml. Therefore, the RT assay cannot be used interchangeably with the other assays to monitor individual patients. The RT assay was 100% sensitive in detecting viral loads of > or =400 copies/ml compared to gold-standard assays. After 24 weeks of treatment, viral load measured by the RT assay was undetectable in 95% of 65 patients with undetectable RNA PCR VL (<400 copies/ml), 90% of 67 patients with undetectable bDNA VL, and 96% of 57 patients with undetectable VL in both RNA PCR and bDNA assays. The negative predictive value of the RT assay was 100% compared to either assay; the positive predictive value was 86% compared to RNA PCR and 70% compared to bDNA. CONCLUSION: The RT assay compared well with gold standard assays. Our study highlights the importance of not interchanging viral load assays when monitoring an individual patient. Furthermore, the RT assay may be limited by low positive predictive values when used in populations with low prevalence of virologic failure.

A reverse transcriptase assay for early diagnosis of infant HIV infection in resource-limited settings.

Early diagnosis of pediatric HIV infection is confounded by persistence of maternal antibodies until 18 months, necessitating the use of expensive assays such as HIV-1 DNA PCR, an untenable option in resource-limited settings. This is the first report of a low-cost, commercial, reverse transcriptase (RT) assay for the diagnosis of HIV-1 infection in infants. RT assays were performed on 42 samples from 30 HIV-exposed Kenyan infants under 15 months of age. When correlated with serologic testing conducted after 18 months, the sensitivity, specificity, positive and negative predictive values of the RT assay were 92%, 93%, 87% and 96%. A low-cost assay for infant HIV diagnosis is urgently needed, and these results merit further evaluation.