Evaluation of HIV testing algorithms in Ethiopia: the role of the tie-breaker algorithm and weakly reacting test lines in contributing to a high rate of false positive HIV diagnoses

Hdl Handle:
http://hdl.handle.net/10144/347024
Title:
Evaluation of HIV testing algorithms in Ethiopia: the role of the tie-breaker algorithm and weakly reacting test lines in contributing to a high rate of false positive HIV diagnoses
Authors:
Shanks, Leslie; Siddiqui, M; Kliescikova, Jarmila; Pearce, Neil; Ariti, Cono; Muluneh, Libsework; Pirou, Erwan; Ritmeijer, Koert; Masiga, Johnson; Abebe, Almaz
Journal:
BMC Infectious Diseases
Abstract:
BackgroundIn Ethiopia a tiebreaker algorithm using 3 rapid diagnostic tests (RDTs) in series is used to diagnose HIV. Discordant results between the first 2 RDTs are resolved by a third `tiebreaker¿ RDT. Médecins Sans Frontières uses an alternate serial algorithm of 2 RDTs followed by a confirmation test for all double positive RDT results. The primary objective was to compare the performance of the tiebreaker algorithm with a serial algorithm, and to evaluate the addition of a confirmation test to both algorithms. A secondary objective looked at the positive predictive value (PPV) of weakly reactive test lines.MethodsThe study was conducted in two HIV testing sites in Ethiopia. Study participants were recruited sequentially until 200 positive samples were reached. Each sample was re-tested in the laboratory on the 3 RDTs and on a simple to use confirmation test, the Orgenics Immunocomb Combfirm® (OIC). The gold standard test was the Western Blot, with indeterminate results resolved by PCR testing.Results2620 subjects were included with a HIV prevalence of 7.7%. Each of the 3 RDTs had an individual specificity of at least 99%. The serial algorithm with 2 RDTs had a single false positive result (1 out of 204) to give a PPV of 99.5% (95% CI 97.3%-100%). The tiebreaker algorithm resulted in 16 false positive results (PPV 92.7%, 95% CI: 88.4%-95.8%). Adding the OIC confirmation test to either algorithm eliminated the false positives. All the false positives had at least one weakly reactive test line in the algorithm. The PPV of weakly reacting RDTs was significantly lower than those with strongly positive test lines.ConclusionThe risk of false positive HIV diagnosis in a tiebreaker algorithm is significant. We recommend abandoning the tie-breaker algorithm in favour of WHO recommended serial or parallel algorithms, interpreting weakly reactive test lines as indeterminate results requiring further testing except in the setting of blood transfusion, and most importantly, adding a confirmation test to the RDT algorithm. It is now time to focus research efforts on how best to translate this knowledge into practice at the field level.Trial registrationClinical Trial registration #: NCT01716299.
Publisher:
BioMed Central (Springer Science)
Issue Date:
3-Feb-2015
URI:
http://hdl.handle.net/10144/347024
DOI:
10.1186/s12879-015-0769-3
PubMed ID:
25645240
Language:
en
ISSN:
1471-2334
Appears in Collections:
HIV/AIDS

Full metadata record

DC FieldValue Language
dc.contributor.authorShanks, Leslieen_GB
dc.contributor.authorSiddiqui, Men_GB
dc.contributor.authorKliescikova, Jarmilaen_GB
dc.contributor.authorPearce, Neilen_GB
dc.contributor.authorAriti, Conoen_GB
dc.contributor.authorMuluneh, Libseworken_GB
dc.contributor.authorPirou, Erwanen_GB
dc.contributor.authorRitmeijer, Koerten_GB
dc.contributor.authorMasiga, Johnsonen_GB
dc.contributor.authorAbebe, Almazen_GB
dc.date.accessioned2015-03-23T19:16:45Z-
dc.date.available2015-03-23T19:16:45Z-
dc.date.issued2015-02-03-
dc.identifier.citationEvaluation of HIV testing algorithms in Ethiopia: the role of the tie-breaker algorithm and weakly reacting test lines in contributing to a high rate of false positive HIV diagnoses. 2015, 15 (1):39 BMC Infect. Dis.en_GB
dc.identifier.issn1471-2334-
dc.identifier.pmid25645240-
dc.identifier.doi10.1186/s12879-015-0769-3-
dc.identifier.urihttp://hdl.handle.net/10144/347024-
dc.description.abstractBackgroundIn Ethiopia a tiebreaker algorithm using 3 rapid diagnostic tests (RDTs) in series is used to diagnose HIV. Discordant results between the first 2 RDTs are resolved by a third `tiebreaker¿ RDT. Médecins Sans Frontières uses an alternate serial algorithm of 2 RDTs followed by a confirmation test for all double positive RDT results. The primary objective was to compare the performance of the tiebreaker algorithm with a serial algorithm, and to evaluate the addition of a confirmation test to both algorithms. A secondary objective looked at the positive predictive value (PPV) of weakly reactive test lines.MethodsThe study was conducted in two HIV testing sites in Ethiopia. Study participants were recruited sequentially until 200 positive samples were reached. Each sample was re-tested in the laboratory on the 3 RDTs and on a simple to use confirmation test, the Orgenics Immunocomb Combfirm® (OIC). The gold standard test was the Western Blot, with indeterminate results resolved by PCR testing.Results2620 subjects were included with a HIV prevalence of 7.7%. Each of the 3 RDTs had an individual specificity of at least 99%. The serial algorithm with 2 RDTs had a single false positive result (1 out of 204) to give a PPV of 99.5% (95% CI 97.3%-100%). The tiebreaker algorithm resulted in 16 false positive results (PPV 92.7%, 95% CI: 88.4%-95.8%). Adding the OIC confirmation test to either algorithm eliminated the false positives. All the false positives had at least one weakly reactive test line in the algorithm. The PPV of weakly reacting RDTs was significantly lower than those with strongly positive test lines.ConclusionThe risk of false positive HIV diagnosis in a tiebreaker algorithm is significant. We recommend abandoning the tie-breaker algorithm in favour of WHO recommended serial or parallel algorithms, interpreting weakly reactive test lines as indeterminate results requiring further testing except in the setting of blood transfusion, and most importantly, adding a confirmation test to the RDT algorithm. It is now time to focus research efforts on how best to translate this knowledge into practice at the field level.Trial registrationClinical Trial registration #: NCT01716299.en_GB
dc.languageENG-
dc.language.isoenen
dc.publisherBioMed Central (Springer Science)en_GB
dc.rightsArchived with thanks to BMC Infectious Diseasesen_GB
dc.titleEvaluation of HIV testing algorithms in Ethiopia: the role of the tie-breaker algorithm and weakly reacting test lines in contributing to a high rate of false positive HIV diagnosesen
dc.identifier.journalBMC Infectious Diseasesen_GB

Related articles on PubMed

All Items in MSF are protected by copyright, with all rights reserved, unless otherwise indicated.