Lucía Chacón1, María Luisa Mateos2, África Holguín3. 1. Molecular Epidemiology Laboratory, Microbiology Department, Ramón y Cajal Health Research Institute (IRYCIS), Spain. 2. Microbiology Department, Hospital Ramón y Cajal, Madrid, Spain. 3. Molecular Epidemiology Laboratory, Microbiology Department, Ramón y Cajal Health Research Institute (IRYCIS), Spain. Electronic address: africa.holguin@salud.madrid.org.
Abstract
BACKGROUND: Despite the high specificity of fourth-generation enzyme immunoassays (4th-gen-EIA) for screening during HIV diagnosis, their positive predictive value is low in populations with low HIV prevalence. Thus, screening should be optimized to reduce false positive results. OBJECTIVES: The influence of sample cutoff (S/CO) values by a 4th-gen-EIA with the false positive rate during the routine HIV diagnosis in a low HIV prevalence population was evaluated. STUDY DESIGN: A total of 30,201 sera were tested for HIV diagnosis using Abbott Architect® HIV-Ag/Ab-Combo 4th-gen-EIA at a hospital in Spain during 17 months. Architect S/CO values were recorded, comparing the HIV-1 positive results following Architect interpretation (S/CO≥1) with the final HIV-1 diagnosis by confirmatory tests (line immunoassay, LIA and/or nucleic acid test, NAT). ROC curve was also performed. RESULTS: Among the 30,201 HIV performed tests, 256 (0.85%) were positive according to Architect interpretation (S/CO≥1) but only 229 (0.76%) were definitively HIV-1 positive after LIA and/or NAT. Thus, 27 (10.5%) of 256 samples with S/CO≥1 by Architect were false positive diagnose. The false positive rate decreased when the S/CO ratio increased. All 19 samples with S/CO ≤10 were false positives and all 220 with S/CO>50 true HIV-positives. The optimal S/CO cutoff value provided by ROC curves was 32.7. No false negative results were found. CONCLUSIONS: We show that very low S/CO values during HIV-1 screening using Architect can result HIV negative after confirmation by LIA and NAT. The false positive rate is reduced when S/CO increases.
BACKGROUND: Despite the high specificity of fourth-generation enzyme immunoassays (4th-gen-EIA) for screening during HIV diagnosis, their positive predictive value is low in populations with low HIV prevalence. Thus, screening should be optimized to reduce false positive results. OBJECTIVES: The influence of sample cutoff (S/CO) values by a 4th-gen-EIA with the false positive rate during the routine HIV diagnosis in a low HIV prevalence population was evaluated. STUDY DESIGN: A total of 30,201 sera were tested for HIV diagnosis using Abbott Architect® HIV-Ag/Ab-Combo 4th-gen-EIA at a hospital in Spain during 17 months. Architect S/CO values were recorded, comparing the HIV-1 positive results following Architect interpretation (S/CO≥1) with the final HIV-1 diagnosis by confirmatory tests (line immunoassay, LIA and/or nucleic acid test, NAT). ROC curve was also performed. RESULTS: Among the 30,201 HIV performed tests, 256 (0.85%) were positive according to Architect interpretation (S/CO≥1) but only 229 (0.76%) were definitively HIV-1 positive after LIA and/or NAT. Thus, 27 (10.5%) of 256 samples with S/CO≥1 by Architect were false positive diagnose. The false positive rate decreased when the S/CO ratio increased. All 19 samples with S/CO ≤10 were false positives and all 220 with S/CO>50 true HIV-positives. The optimal S/CO cutoff value provided by ROC curves was 32.7. No false negative results were found. CONCLUSIONS: We show that very low S/CO values during HIV-1 screening using Architect can result HIV negative after confirmation by LIA and NAT. The false positive rate is reduced when S/CO increases.
Authors: Mark M Manak; Linda L Jagodzinski; Ashley Shutt; Jennifer A Malia; Mike Leos; Jason Ouellette; Siriwat Akapirat; Donn L Colby; Nittaya Phanuphak; Leigh Anne Eller; Merlin L Robb; Mark de Souza; Jintanat Ananworanich; Sheila A Peel Journal: J Clin Microbiol Date: 2019-09-24 Impact factor: 5.948
Authors: Michael A Linström; Wolfgang Preiser; Nokwazi N Nkosi; Helena W Vreede; Stephen N J Korsman; Annalise E Zemlin; Gert U van Zyl Journal: PLoS One Date: 2021-01-11 Impact factor: 3.240