Our study was not designed to evaluate the performances of the two rapid HIV tests, namely Genie II® HIV-1/HIV-2 (BioRad) and SD Bioline® HIV-1/2 3.0 (Standard Diagnostics). Our aim as epidemiologists and clinicians was to clearly make the difference between HIV-1, HIV-2 and dually infected patients, as it is critical for selecting an appropriate treatment strategy. For this purpose, we used the most suitable HIV tests, ImmunoCombII® HIV-1&2 BiSpot (Alere) [1] and an in-house Elisa test [2–4].
Based on the field experience in Guinea-Conakry and Guinea-Bissau [5–7], the authors argue on the need to assess the individual performance of each test used for the initial discrimination of HIV-positive patients. Our team previously conducted in 2004 a field evaluation of rapid HIV serologic tests in Côte d'Ivoire and highlighted the lower accuracy of Genie II for differentiating between HIV-1, HIV-2 and dually reactive patients [4].
In our most recent study, the initial HIV diagnostic tests were reported for 373 patients (68.3% of the overall sample), namely GenieII for 172 (46.1%) and SD Bioline for 79 (21.2%). In Burkina-Faso, 116 samples (50.0%) had the initial HIV test reported; seven (6.0%) of these samples were tested with Genie II and 74 (63.8%) with Bioline. In Côte d'Ivoire, 217 (81.0%) had the initial HIV test reported, among which 145 (66.8%) were tested with Genie II and only four (1.8%) with Bioline. In Mali, this was the case for 40 samples (85.1%), Genie II for 20 samples (50%) and Bioline for one sample (2.5%).
Second, we compared HIV screening results based on these two tests, to the concordant results of a combination of in-house Elisa and ImmunoCombII. Among the 57 samples tested using Bioline, 14 out of 18 initially classified as HIV-2 (77.8%) were confirmed HIV-2 and only six out of 39 initially classified as HIV-1&2 (15.4%) were confirmed HIV-1&2 (kappa=0.19; p≤0.001). The final concordant results with in-house Elisa and ImmunoCombII were available for 170 samples initially tested with Genie II. Among the 129 samples initially classified as HIV-2, 121 (93.8%) were confirmed HIV-2 and among the 41 initially classified as HIV-1&2, 16 (39.0%) were confirmed HIV-1&2 (kappa=0.50; p≤0.001).
It is clear that these two tests (Genie II and SD Bioline) have different but generally low diagnostic accuracy for HIV discrimination. As we stated in our article, there is a need to systematically retest HIV-1&2 dually reactive patients with more accurate algorithms before treatment initiation.
Finally, we agree with the comment on the use of problematic lots of Bioline tests; however, we did not have access to pharmaceutical data of the AIDS control programme in each country and were therefore unable to provide more information on this question. Nevertheless the participating countries have now updated their national algorithm to introduce more accurate discriminative tests such as Genie III (Côte d'Ivoire,) and ImmunoComII (Mali).
Acknowledgements
We thank François Dabis who is the principal investigator of the WADA Collaboration for his precious scientific contribution and advice. We also thank Patrick Coffie for his critical reading and advice on complementary analysis.
Competing interests
The authors declare no competing interest.
Authors' contributions
BT and DKE performed the statistical analysis, interpreted the results and wrote the first draft of the manuscript. SPE contributed to critical reading and the final version of the manuscript.
Funding
The HIV-2 cohort of the WADA Collaboration is partly funded by the National Cancer Institute (NCI), the Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), and the National Institute of Allergy and Infectious Diseases (NIAID) of the US National Institutes of Health (NIH), as part of the International Epidemiologic Databases to Evaluate AIDS (IeDEA) under Award # U01AI069919. The ANRS (France REcherche Nord & sud Sida-hiv Hépatites: FRENSH) supported part of the laboratory work performed within this study.
References
- 1.World Health Organization. WHO; 2013. WHO ∣ HIV test kit evaluations. [Internet]. [cited 2014 Jun 21]. Available from: http://www.who.int/diagnostics_laboratory/evaluations/hiv/en/ [Google Scholar]
- 2.Barin F, Lahbabi Y, Buzelay L, Lejeune B, Baillou-Beaufils A, Denis F, et al. Diversity of antibody binding to V3 peptides representing consensus sequences of HIV type 1 genotypes A to E: an approach for HIV type 1 serological subtyping. AIDS Res Hum Retroviruses. 1996;12(13):1279–89. doi: 10.1089/aid.1996.12.1279. [DOI] [PubMed] [Google Scholar]
- 3.Simon F, Souquière S, Damond F, Kfutwah A, Makuwa M, Leroy E, et al. Synthetic peptide strategy for the detection of and discrimination among highly divergent primate lentiviruses. AIDS Res Hum Retroviruses. 2001;17(10):937–52. doi: 10.1089/088922201750290050. [DOI] [PubMed] [Google Scholar]
- 4.Rouet F, Ekouevi DK, Inwoley A, Chaix M-L, Burgard M, Bequet L, et al. 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. J Clin Microbiol. 2004;42(9):4147–53. doi: 10.1128/JCM.42.9.4147-4153.2004. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Chaillet P, Tayler-Smith K, Zachariah R, Duclos N, Moctar D, Beelaert G, et al. Evaluation of four rapid tests for diagnosis and differentiation of HIV-1 and HIV-2 infections in Guinea-Conakry, West Africa. Trans R Soc Trop Med Hyg. 2010;104(9):571–6. doi: 10.1016/j.trstmh.2010.05.007. [DOI] [PubMed] [Google Scholar]
- 6.Hønge BL, Jespersen S, Nordentoft PB, Medina C, da Silva D, da Silva ZJ, et al. Loss to follow-up occurs at all stages in the diagnostic and follow-up period among HIV-infected patients in Guinea-Bissau: a 7-year retrospective cohort study. BMJ Open. 2013;3(10):e003499. doi: 10.1136/bmjopen-2013-003499. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Hønge BL, Bjarnason Obinah MP, Jespersen S, Medina C, da Silva Té D, José da Silva Z, et al. Performance of 3 rapid tests for discrimination between HIV-1 and HIV-2 in Guinea-Bissau, West Africa. J Acquir Immune Defic Syndr. 2014;65(1):87–90. doi: 10.1097/QAI.0b013e3182a97b81. [DOI] [PubMed] [Google Scholar]