AFRICA: Dried blood spots for HIV monitoring

Scientists have shown that dried blood spots could be used under field conditions in rural Africa to detect levels of human immunodeficiency virus, or HIV, in the blood of patients on antiretroviral treatment, providing a simple and reliable tool for virological monitoring in resource-limited settings.

They published their findings online in Clinical Infectious Diseases in August.

Monitoring HIV patients on antiretroviral (ARV) treatment is standard in industrialised countries, to determine when treatment fails and a switch to second-line therapy is needed. But effective monitoring is rarely available in resource-limited settings as it is relatively expensive, require large quantities of blood and needs special conditions for storing and transporting samples.

Dried blood spots (DBS) could be a convenient alternative to plasma, allowing storage at room temperature for weeks without the virus's genetic material degrading.

Lead researcher Asgeir Johannessen, from the Ulleval Department of Infectious Diseases at Oslo University Hospital in Norway, and colleagues assessed the performance of DBS by examining the viral level of plasma and DBS specimens obtained from 98 patients on ART at Haydom Lutheran Hospital in northern rural Tanzania from November 2007 to June 2008.

The technique requires minimal training and infrastructure, and could easily be employed in other low-resource clinics as it only needs extraction and amplification of the virus's genetic material from a tiny amount of blood blotted on to filter paper which can be conveniently collected and transported - even posted - to laboratories in a zip lock bag.

Researchers found that DBS performed well compared to plasma in monitoring viral load in rural Tanzania.

"Several studies have demonstrated the efficacy of viral load quantification on DBS, but we are the first to show that virological monitoring on DBS can be feasible and reliable under field conditions in rural Africa, the setting where this technique can be of most use," Johannessen told University World News.

Johannessen added that such a field study has been missing, since most work on DBS and viral load quantification has been carried out in well-equipped laboratories in Europe and North America.

"Our study describes a method which can give access to viral load quantification even in remote health centres in developing countries," Johannessen pointed out.