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In-house assay effective for monitoring HBV in resource-limited countries
Researchers in France developed an in-house assay that was accurate, simpler and cheaper for detecting hepatitis B virus infection plasma than commercial assays among patients in West Africa, suggesting it could be a valuable testing method in resource-limited regions.
“Several in-house [quantitative real-time-(qRT-PCR)] assays were previously proposed as efficient alternatives to the expensive commercial qPCR-based assays to monitor HBV treatment in developing countries,” Isabelle Chemin, PhD, of the Cancer Research Center of Claude Bernard Lyon University in France, and colleagues wrote. “Here, not only do we validate an in-house SYBR Green-based qRT-PCR assay (Applied Biosystems) for the detection of HBV genotypes specific to sub-Saharan Africa countries and compare its efficacy with commercially available qPCR assays, but we also report the first implementation of such a technology in the Gambia and Senegal in collaboration with European countries.”
The researchers evaluated more than 1,500 patients with hepatitis B surface antigen enrolled in the Prevention of Liver Fibrosis and Cancer in Africa program in the Gambia and Senegal. Of these patients, 210 had chronic HBV and were treated with tenofovir (Gilead Sciences) and monitored for treatment response via qRT-PCR using the SYBR Green- and HBV-specific primers.
Using both the in-house assay and commercial assays (COBAS TaqMan HBV version 2.0, Roche; or Abbott Real Time HBV assay, Abbott), a subgroup of 24 patients treated with tenofovir also was monitored, with viral loads tested every 3 months for 1 year after treatment initiation.
Results showed the in-house assay was reliable with good intra- and interassay reproducibility over a wide range (45 to 4.5 × 108 copies mL-1), easier to implement and produced quicker results compared with the commercial assays. The in-house assay also detected similar viral loads (R2 = .90) and was very sensitive, detecting HBV viral loads as low as 30 copies mL-1 (~5 IU mL-1) with only 200 µL of plasma.
The researchers reported the costs of the commercial assays were twofold to threefold greater than the in-house assay. These costs only represented the assay and not the equipment cost. The average cost of running a plasma sample in a diagnostic center in the Gambia is between 125 euros and 150 euros, and sometimes patients require one to three tests annually, indicating a cheaper test may “have a huge impact in terms of economic benefit to the patients,” according to the research.
“An affordable viral load-monitoring technique is urgently required in such countries,” the researchers wrote. “Based on our experience, we recommend this assay as a reliable alternative to commercial assays, for monitoring HBV viremia in resource-limited, highly endemic countries to reduce the cost and technical obstacles associated with commercial kits.” – by Melinda Stevens
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