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Dried blood spot tests practical for HCV screening in developing countries

Researchers determined the prevalence and characteristics of hepatitis C viremia in the Democratic Republic of the Congo using dried blood spot viral load testing, according to a recently published study. Based on crude population estimates from 2016, the researchers expect 100,000 to 200,000 adults aged 40 years or older to be actively infected and eligible for treatment.

Jonathan B. Parr

“The Democratic Republic of the Congo is one of the largest countries in Africa and has limited infrastructure, so the diagnosis and treatment of HIV is challenging. In order to reach people living with HIV in rural areas, the AIDS Control Program transports dried blood spot samples from across the country to several central laboratories, where HIV viral load testing is performed,” Jonathan B. Parr, MD, MPH, from the University of North Carolina School of Medicine, told Healio.com/Hepatology. “We wanted to find a way to use this existing laboratory infrastructure to support the diagnosis and treatment of viral hepatitis.”

“Unfortunately,” Parr continued. “the vast majority of people infected with HCV in the Democratic Republic of the Congo remain undiagnosed and untreated. Our hope is that these findings will be useful in other settings like the Democratic Republic of the Congo and open the door to treatment with new, highly effective treatment regimens.”

The researchers used mock dried blood spots (DBS) to determine the HCV-testing performance of the m2000 RealTime System (Abbott Laboratories). Test results from 39 6-mm DBS punches made with whole blood RNA-containing concentrations confirmed that the m2000 system could be applied to detect HCV.

“This approach has broad utility throughout much of sub-Saharan Africa, as the required laboratory infrastructure is already established for HIV viral load testing. By employing a similar workflow to what is required for ongoing HIV projects, ministries of health in resource-limited settings can identify subjects eligible for HCV treatment,” the researchers wrote.

The researchers randomly selected 1,015 of 3,939 adults aged 40 years or older enrolled in the 2013 to 2014 Democratic Republic of the Congo Demographic and Health Survey (DRC DHS) from the country’s 11 provinces. The cohort included 19 of the 38 DRC DHS participants with HIV.

The 15 cases of HCV viremia identified represented a national weighted prevalence of 0.9% (95% CI, 0.3-1.6). The one case of HIV/HCV coinfection represented a national weighted prevalence of 0.7% (95% CI, 0.6-0.8) and a 4.7% prevalence of HCV among the 21 patients with HIV who received testing.

According to the phylogenetic analysis, genotype 4 infections were the most common including subtypes 4k (30%), 4c (20%), 4f (10%), 4l (10%) and 4r (10%).

“Hepatitis C infections remain underdiagnosed and undertreated in marginalized populations, despite the development of well-tolerated, curative antiviral medications,” Parr said. “We validated a simple testing approach that requires collection of only a single drop of blood on filter paper. This approach is easily implemented using existing laboratory infrastructure in large surveys, including those in resource-limited settings.” – by Talitha Bennett

Disclosure: Parr reports no relevant financial disclosures. Please see the full study for the other authors’ relevant financial disclosures.