Dried blood spot (DBS) test has been practiced for ~100 years[1], but has started gaining traction as an alternate to traditional assays only this decade. Human / Animal blood is spotted on prepared filter cards, the cards are air dried, stored in airtight bags, and shipped under administered humidity and temperature levels[2] in DBS analysis. For bioanalytical analysis, we punch tiny discs out of the DBS and analyze them using a validated LC-MS/MS method. Traditionally, scientists have used DBS collection for preclinical studies, newborn screening, as well as DBS sample collection in resource-limiting settings. Recently, however, a variety of innovative DBS sampling applications have started to emerge. These DBS test applications include epidemiological surveys (e.g. HIV monitoring), therapeutic drug monitoring (TDM), as well as toxicology[3]. DBS tests can be useful at different stages, from the simplest research scenarios to very complex clinical cases, due to their simplicity and flexibility.
The primary advantages of the DBS test include lower sample volume collection and easier handling during DBS sample storage and transportation. Other seemingly less obvious advantages of DBS analysis are listed below.
We ran the study on an antiretroviral medicine, which is used in conjunction with other treatments for HIV. Due to cryo-freezers’ unavailability, it is generally difficult to properly collect, store, and maintain high-integrity blood samples in remote areas. The high shipping cost for transporting samples from these remote DBS collection sites to faraway sample analysis facilities was burdensome. Therefore, the investigators decided to use the DBS sampling technique. They collected each DBS sample at six spots for accurate/redundant DBS analysis.
Our team processed DBS samples, analyzed them using an LC-MS/MS method developed in our laboratory, and documented the DBS test results. We analyzed and compared results from each sample in five replicates. The observed coefficient of variation (CV) among these DBS samples was less than 7.2%, indicating the bioanalytical method as rugged and reproducible as well as the DBS collection process as accurate.
Generally, the compounds tested with DBS test have shown promise. We, however, strongly recommend conducting validation and feasibility analysis prior to reporting results. As per FDA guidance, this validation should cover storage and handling temperature, homogeneity of DBS sample spotting, hematocrit, stability, carryover, and reproducibility including ISR[4]. Even more, concordance between DBS analysis and traditional plasma assays should be established if possible[5]. The most crucial point is ensuring the DBS test complies with the strict quality control (QC) guidelines for data accuracy, reliability, and consistency before relying on its results in conducting pharmacokinetic (PK) and bioanalytical studies.
NorthEast BioLab offers the following DBS sample services.
[1] Hannon WH, Therell BL. Overview of the history and applications of dried blood spot samples. In: Li W, Lee MS, editors. Dried blood spots. Applications and techniques. Vol. 3. Hoboken: Wiley; 2014. pp. 3–15.
[2] Grüner N, Stambouli O, Ross RS. Dried blood spots–preparing and processing for use in immunoassays and in molecular techniques. J Vis Exp. 2015 Mar 13;(97). doi: 10.3791/52619.
[3] Stove CP1, Ingels AS, De Kesel PM, Lambert WE. Dried blood spots in toxicology: from the cradle to the grave? Crit Rev Toxicol. 2012 Mar;42(3):230-43. doi: 10.3109/10408444.2011.650790.
[4] U.S. Food and Drug Administration, Guidance for Industry –
Bioanalytical Method Validation, September 2013 Biopharmaceutics Revision 1
[5] Neogi U, Gupta S, Rodridges R, Sahoo PN, Rao SD, Rewari BB, Shastri S, Costa AD, Shet A., Dried blood spot HIV-1 RNA quantification: a useful tool for viral load monitoring among HIV-infected individuals in India, Indian J Med Res. 2012 Dec;136(6):956-62