Assesment of a novel HIV rapid confirmatory assay: imunoblot rápido DPP® HIV 1/2
Background: Imunoblot Rápido DPP® HIV ½ (Bio-Manguinhos, Brazil) is a single-use immunocromatographic rapid test for the detection of individual antibodies (gp36, gp160, gp120, gp41 and p24) in whole blood, serum or plasma. DPP® assays presents two different paths: one for the sample and other for conjugated. The test takes less than 30 minutes to perform, results are visually read and it can differentiate an HIV-1 or 2 infection. The objective of this study was to evaluate the performance of the Imunoblot Rápido DPP® HIV ½ in a multi-center study in Brazil.
Methods: Following informed consent, whole blood was obtained from patients enrolled in five clinic centers from distinct regions of Brazil, and tested by the Imunoblot Rápido DPP® HIV ½ well as by a dual-immunoassay+WB algorithm that defined the reference standard for HIV infection. Obtained results were interpreted in accordance with the manufacturer´s instructions.
Results: A total of 964 samples were obtained: 139 (14.4%) were positive and 825 negative for HIV-1 antibodies according to the reference algorithm. Imunoblot Rápido DPP® was easy to perform. On examination by two different readers, discrepancies in band pattern interpretation were present in 1.38% of analyses; affecting the final interpretation. Consensus results were used for performance calculations. From 139 positive samples, 134 were positive and 4 indeterminate (clinical sensitivity: 96.4% (95% CI: 93.4-98.1)) Among HIV negative samples, the DPP assay gave indeterminate results in 3/825 samples but also gave “confirmed positive” results in 3/825 negative samples (clinical specificity: 99.3% (95% CI: 98.8-99.6)).
Conclusion: The reliability of the test was similar with most of confirmatory HIV tests commercially available. These results support the use of the Imunoblot Rápido DPP® as part of Brazil's national HIV test algorithm, as a rapid confirmatory test, which might facilitate expansion of VCT services and improve the efficiency in HIV results return.
L.R. Motta1, A.C. Vanni1, L.G.A. Borges1, S.K. Kato1,2,3, R.D. Sperhacke1, R.M.M. Ribeiro4, L.A. Inocêncio4, HIV Rapid Test Evaluation Group
1Universidade de Caxias do Sul, Laboratório de Pesquisa em HIV/AIDS, Caxias do Sul, Brazil, 2Pontifícia Universidade Católica do Rio Grande do Sul, Departamento de Estatística, Porto Alegre, Brazil, 3Fundação Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil, 4Brazil Ministry of Health Surveillance Secretariat, Deparment of STD, AIDS and Viral Hepatitis, Brasília, Brazil