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Using a simplified human immunodeficiency virus type 1 p24 antigen assay to diagnose pediatric HIV-infection in
Victor Mwapasa1, Ada Cachafeiro, Yohane Makuta
1Department of Community Health, Malawi College of Medicine, Blantyre, Malawi. vmwapasa@medcol.mw
Insights
A simplified Up24 assay accurately detects pediatric HIV-1 in dried blood spots. This cost-effective diagnostic tool shows promise for improving global access to HIV testing in resource-limited settings.
Area of Science:
- Pediatric infectious diseases
- Diagnostic assay development
- Global health
Background:
- A need exists for accurate, simple, and cost-effective pediatric HIV-1 diagnostics.
- The original Up24 assay using HIV-1 p24 ELISA and ELAST was effective but complex.
- Simplifying the Up24 assay for resource-limited settings was investigated.
Purpose of the Study:
- To evaluate a simplified Up24 antigen assay without the ELAST system.
- To determine the diagnostic accuracy of this simplified assay for pediatric HIV-1 detection in dried blood spots (DBS).
Main Methods:
- A case-control study was conducted using DBS samples from infants in Malawi.
- The study included 113 HIV-infected and 109 HIV-negative infants.
- HIV-1 DNA PCR assay served as the reference standard.
Main Results:
- The simplified Up24 assay demonstrated 84% sensitivity and 98% specificity.
- Positive-predictive value was 89% and negative-predictive value was 97% at 15% HIV-1 prevalence.
- The assay is easier to perform and less costly than previous methods.
Conclusions:
- The simplified Up24 assay offers good positive and robust negative predictive values.
- This simplified assay is easier to perform and more cost-effective.
- Further testing may establish this assay as a tool to enhance global access to pediatric HIV-1 diagnostics.
Background:
There is a worldwide need for a pediatric HIV-1 diagnostic test that has a high diagnostic accuracy, is technically simple and cost efficient. The Up24 HIV-1 assay, which requires both the HIV-1 p24 ELISA and the ELAST signal amplification kit, has previously been shown to be a robust tool to diagnose pediatric HIV-1 from dried whole blood spots (DBS) (Cachafeiro et al., JCM 2009;47:459-62(13)). In order to make the assay more accessible to a resource-limited clinical setting, we eliminated the ELAST system, which simplified the Up24 assay, reduced its cost, and tested the accuracy of the modified assay in a rural Malawian hospital.
Objectives:
In this proof of concept study, we tested the ability of a simplified Up24 antigen assay, without ELAST, to detect HIV-1 on DBS obtained via heel prick from 6-week-old Malawian infants.
Study Design:
A case-control study of DBS collected from 113 HIV-infected and 109 HIV-negative infants, using the HIV-1 DNA PCR assay as the reference standard.
Results:
The simplified HIV-1 Up24 assay had a sensitivity and specificity of 84% and 98%, respectively. When HIV-1 prevalence is 15%, the positive- and negative-predictive values are 89% and 97%, respectively.
Conclusion:
The simplified Up24 assay has a good positive- and a robust negative-predictive values, is easier to perform and has a reduced cost compared to both HIV DNA PCR and Up24 assays. With additional testing, the simplified Up24 assay has the potential to increase global access to pediatric HIV-1 diagnostics.
