Out for Less Blood

Courtesy Photo | FilmArray assays being performed by Umaru Bangura and Rashid Ansumana. (Photo by Tomasz Leski) Victoria Baio extracts DNA from patient samples. (Photo by Chris Taitt)  

FT. BELVOIR, VA, UNITED STATES

10.27.2021

Courtesy Story

Defense Threat Reduction Agency's Chemical and Biological Technologies Department

Warfighters are often deployed to locations where they risk exposure to rare tropical diseases, emerging viral pathogens, or biological warfare agents. The ability to quickly diagnose an illness at the point of exposure and administering timely medical countermeasures can aid in protecting the warfighter, stopping the spread of disease, and supporting the mission. While there have been significant advances made in versatile diagnostic capabilities, collecting a blood sample using venipuncture—blood drawn from a vein—requires trained medical personnel, and the warfighter may have to travel a great distance for this procedure. If capillary blood from a simple finger stick could yield the same test results, then the warfighter could be diagnosed and treated closer to the deployment location and in less time.

The Defense Threat Reduction Agency’s (DTRA) Chemical and Biological Technologies Department in its role as the Joint Science and Technology Office (JSTO) for the Chemical and Biological Defense Program invested in a study to determine if blood from a finger stick instead of venipuncture could be used for relevant diagnosis of chemical and biological threats. To test the equivalence of the different methods, DTRA-JSTO used the Laboratory Analysis and Clinical Evaluation program at one site in South America and another in West Africa.

The Naval Medical Research Unit #6 monitors a well-studied population of a half million residents in the remote city of Iquitos, Peru, on the Amazon River. Since the mosquito-borne dengue virus is the predominant infection seen at the clinic, researchers compared the precision of laboratory-based polymerase chain reaction (PCR) conducted on both blood from venipuncture and from finger stick. Of the 327 paired samples, 74 were positive for dengue serotype 1, and 10 for dengue serotype 2. Researchers determined the positivity rates were nearly identical, which confirmed that consistent results could be obtained from the venous and capillary blood samples.

Similarly, the Naval Research Laboratory conducted a study in a smaller city in Bo, Sierra Leone, of about 175,000. They performed PCR using the FilmArray Global Fever Panel and a multiplex Q-PCR assay to analyze the paired venous and capillary blood of 141 people exhibiting symptoms of malaria to detect the presence of Plasmodium parasites. The researchers found no difference in malaria detection between venous and capillary blood using two different PCR-based detection assays. This data supports the use of capillary blood for PCR-based malaria diagnostics.

While the sample sizes were small, these studies revealed preliminary evidence of the accuracy of using finger-stick capillary blood rather than venous blood for rapid testing with molecular diagnostic assays.

This research supports eliminating the need for transporting warfighters from deployed locations to skilled medical technicians in a hospital or point-of-care setting by using simpler but accurate diagnostic methods to identify and treat biological threats and help stop the spread of disease.

POC: Stephen Francesconi, Ph.D., [e-mail]

• Date Taken: 10.27.2021
• Date Posted: 10.27.2021 17:27
• Story ID: 408161
• Location: FT. BELVOIR, VA, US