Abstract
Background: Point of care (POC) rapid recency testing can be used as a cost-effective tool to identify recently infected individuals in real-time, and aid prompt treatment. We evaluated the accuracy of the AsantéTM Human immunodeficiency virus (HIV-1) Rapid Recency® Assay as a POC rapid diagnostic test amongst blood donors in South Africa.
Methods: The study was a cross-sectional and validity study of the AsantéTM HIV-1 Rapid Recency® Assay performed on 715 consecutively archived serum and plasma donor specimens from the South African Blood Services (SANBS) to determine their recency and established HIV infection status. Enzyme-Linked Immunoassay (ELISA) and Rapid assays for HIV antibody detection were used as the reference-testing standard for confirming HIV infection. Positive HIV samples were then tested for recent or long-term infection using the Maxim HIV-1 Limiting Antigen (LAg) avidity assay. Validity tests (sensitivity, specificity, negative and positive predictive values) and Cohen-Kappa tests of agreement were conducted to compare the AsantéTM HIV-1 Rapid Recency® Assay HIV recency tests with the reference tests. A logistic regression model of the predictors of HIV recency based on the AsantéTM HIV-1 Rapid Recency® Assay was conducted. The P-value was assumed statistically significant at P-value< 0.05. Stata version 16, statistical software and XLSTAT, version 2018.1 were used for statistical analysis.
Results: Of the 715 studied blood samples, 63.1% (N=451/715) were confirmed to be HIV positive based on the reference standard with 56.4% (N=403/715) of samples being female. The mean age of the participants was 30.87±11.84 years. The sensitivity and specificity of the AsantéTM HIV-1 Rapid Recency® Assay in diagnosing established HIV infection when compared to the ELISA was 98.4% (95%CI: 96.7% - 99.3%) and 99.6% (95%CI: 97.6% - 100%) respectively. When compared to HIV Rapid assay, the sensitivity and specificity of the AsantéTM HIV-1 Rapid Recency® Assay was 98.7% (95%CI: 97.0% - 99.4%) and 99.2% (95%CI: 97.1% - 100%) respectively. There was good agreement between the results from samples run using the AsantéTM HIV-1 Rapid Recency® Assay and ELISA (agreement = 98.9%, k = 0.976, P-value = <0.0001) and Rapid assays (agreement =98.9%, k = 0.976, P-value = <0.0001)
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| Masters Biomedical Technology | Beverley Singh | Student number 219120671
respectively. Of the 451 HIV positive blood samples, 194 specimens (43%) were confirmed as recent HIV infection by the Maxim HIV-1 LAg Avidity Assay. There was high agreement between the AsantéTM HIV-1 Rapid Recency® Assay, and the Maxim HIV-1 LAg Avidity Assay (94.1%, k=0.879, P-value =<0.0001). When viral load data were used to determine recency, there was fair agreement (60.1%, k=0.230). Both the AsantéTM HIV-1 Rapid Recency® Assay and Rapid/ELISA assays had high agreement for diagnosing established infection in all age groups (<30, 30-49 and ≥50) and among males and females. The agreement between the AsantéTM HIV-1 Rapid Recency® Assay and the Maxim HIV-1 LAg Avidity Assay when assessing recent infections was high among 30–49-year-olds as well as individuals who were 50-years and older (96.34% and 95.62%, respectively) and among males and females (96.18% versus 93.33%, respectively).
Conclusion: The AsantéTM HIV-1 Rapid Recency® Assay test results demonstrated high accuracy (>90%) compared with the HIV ELISA and Rapid assays for determining established infection and the Maxim HIV-1 LAg Avidity Assay for classifying new HIV-1 infections. The sensitivity of the assay for established infections was less than 99%, which is below the WHO criteria for POC devices. Stratified analysis by socio-demographic variables showed high agreement in all age groups and in either male or female sex to determine established infection and recent infections. The AsantéTM HIV-1 Rapid Recency® Assay can therefore be used to distinguish between recent and long-term infections, but cannot be considered a POC test for determining HIV infection.
Key Words
AsantéTM HIV-1 Rapid Recency® Assay, Established infection, ELISA, HIV Rapid Assay, the Maxim HIV-1 Limiting Antigen (LAg) Avidity Assay, Point of Care, Sensitivity, Specificity.