Welcome back to our series about dried blood spot (DBS) testing. In Part 1, we provided an overview of what DBS is, how it is performed, and we touched upon some of its many applications. In Part 2, we will dig into how DBS may be used in the diagnosis and monitoring of infectious diseases.
DBS – a quick recap
In brief, DBS testing is a microsampling method that is based on dried spots of whole blood. The method arose through the work of American microbiologist Robert Guthrie in the 1960s who sought to develop new ways to detect the rare metabolic disorder phenylketonuria (PKU). Since then, DBS has increasingly been used for the qualitative or semi-quantitative analysis of hundreds of molecules, including nucleic acids, small molecule therapeutics, proteins, and more (1).
DBS testing in infectious disease
The first references to the use of DBS for infectious disease diagnostics date back to the 1950s, where the method was used to detect syphilis (2). Later, throughout the 1970s and 1980s, DBS was employed in the diagnosis and serological monitoring of a number of infectious diseases, including trypanosomiasis, hepatic amoebiasis, congenital rubella, and hepatitis B. Increase in the use of DBS in diagnostics rose again around the turn of the millennium, primarily in response to the urgent need for therapeutic monitoring of HIV infection (see 3, and references therein).
Within infectious disease diagnostics and monitoring today, DBS samples can be used to measure antibody responses to pathogens, and to detect pathogen-derived antigens or pathogen-derived nucleic acids, using a range of standard laboratory analysis methods.
As well as providing a qualitative answer regarding the presence or absence of a pathogen, DBS testing can also be used to quantitatively monitor viral load or immunoglobulin titers in individuals already confirmed to have a chronic infection such as HIV, as well as monitoring the response to treatment by using viral/bacterial load or immunoglobulin titers as a readout.
Advantages of DBS testing in infectious disease diagnostics
In comparison to venous blood draws, DBS sampling devices make sample collection relatively easy and non-invasive. With the emergence of devices such as Capitainer®B, which is based on Capitainer’s proprietary qDBS technology, consistent and highly accurate DBS sampling is now possible. Because DBS samples can be stored and shipped as non-hazardous material at ambient temperatures, DBS has vast potential to improve diagnostics and care of infection in hard-to-reach populations or remote areas with high infection risk, in young and vulnerable individuals, as well as people living in low-income settings.
As well as the above benefits, DBS testing circumvents the need for a trained phlebotomist, making it an ideal and cost-effective choice for home/remote sampling for regular testing and monitoring of a diverse range of infectious diseases, including but not limited to, infectious diseases associated with poverty, pregnancy-associated infectious diseases and sexually-transmitted diseases.