HIV viral load assays when used with whole blood perform well as a diagnostic assay for infants
Charles Kiyaga1, Youyi Fong2, Christopher Okiira3
1Central Public Health Laboratory, Kampala, Uganda.
Insights
HIV viral load assays can accurately diagnose HIV infection in infants. The Roche SPEX and Abbott technologies demonstrated high sensitivity and specificity, simplifying early infant diagnosis and treatment initiation.
Area of Science:
- Medical Diagnostics
- Virology
- Public Health
Background:
- Early infant diagnosis (EID) of HIV is crucial for timely treatment initiation.
- Current EID testing rates remain suboptimal, with only about 50% of HIV-exposed infants tested within two months.
- Fragmented laboratory systems pose significant barriers to effective EID.
Purpose of the Study:
- To evaluate the accuracy of HIV viral load assays for diagnosing HIV infection in infants.
- To compare the performance of different assay technologies and protocols for infant HIV diagnosis.
Main Methods:
- 866 Ugandan infants were enrolled, with testing conducted using Roche and Abbott molecular technologies on dried blood spot samples.
- Two buffers (PBS and SPEX) were used for the Roche assay, while Abbott used its standard infant diagnosis protocol.
- Both qualitative and quantitative viral load tests were performed on all infant samples.
Main Results:
- The Roche SPEX and Abbott technologies exhibited high sensitivity (>95%) and specificity (>98%) for infant HIV diagnosis.
- The Roche FVE protocol showed lower sensitivity (85%) compared to other methods.
- 858 infants were included in the final analysis.
Conclusions:
- HIV viral load assays, specifically Roche SPEX and Abbott technologies, can be effectively utilized for infant HIV diagnosis.
- Streamlining laboratory practices with these assays can improve early infant diagnosis rates.
- Accurate and efficient diagnosis facilitates prompt initiation of life-saving antiretroviral therapy.
Objective:
Over the past several years, only approximately 50% of HIV-exposed infants received an early infant diagnosis test within the first two months of life. While high attrition and mortality account for some of the shortcomings in identifying HIV-infected infants early and putting them on life-saving treatment, fragmented and challenging laboratory systems are an added barrier. We sought to determine the accuracy of using HIV viral load assays for infant diagnosis of HIV.
Methods:
We enrolled 866 Ugandan infants between March-April 2018 for this study after initial laboratory diagnosis. The median age was seven months, while 33% of infants were less than three months of age. Study testing was done using either the Roche or Abbott molecular technologies at the Central Public Health Laboratory. Dried blood spot samples were prepared according to manufacturer-recommended protocols for both the qualitative and quantitative assays. Viral load test samples for the Roche assay were processed using two different buffers: phosphate-buffered saline (PBS: free virus elution viral load protocol [FVE]) and Sample Pre-Extraction Reagent (SPEX: qualitative buffer). Dried blood spot samples were processed for both assays on the Abbott using the manufacturer's standard infant diagnosis protocol. All infants received a qualitative test for clinical management and additional paired quantitative tests.
Results:
858 infants were included in the analysis, of which 50% were female. Over 75% of mothers received antiretroviral therapy, while approximately 65% of infants received infant prophylaxis. The Roche SPEX and Abbott technologies had high sensitivity (>95%) and specificity (>98%). The Roche FVE had lower sensitivity (85%) and viral load values.
Conclusions:
To simplify and streamline laboratory practices, HIV viral load may be used to diagnose HIV infection in infants, particularly using the Roche SPEX and Abbott technologies.
