Dried blood spot (DBS) sampling has been used to screen newborn babies for congenital metabolic diseases for over 50 years. A spot of blood from a heel stick of the infant is placed on filter paper and allowed to air dry. A circular punch (about 3 mm) is removed, eluted with solvent and analyzed for metabolic markers. More than 50 separate analytes can be be measured from a quarter size spot of blood (Wilken, 2001; Mei, 2002), mainly due to adoption within the last 5 years of mass spectrometry for analysis.
Advantages of DBS sampling include minimal volume requirements (approximately 30 – 100 µL per spot), ease of sample attainment by finger or heel stick with minimal training required, ease of transport and sample stability. Once dried, the sample is stable for months to years at ambient temperature or under refrigeration (De Jesus, 2009; McDade, 2007).
These superior traits have made DBS a common sampling method for gene screening and long-term genetic sample bio-banking. Within the last few years, DBS sampling has been used for clinical and pre-clinical pharmacokinetic studies, taking advantage of smaller sampling needs and simplified sample collection and handling. DBS sampling has also been used for disease surveillance in developing countries (Solomon, 2002).
Many studies show that DBS sampling is compatible with and equivalent to current tests performed with fresh blood samples.
Analyte classes that have shown successful recovery and analysis from DBS include:
amino acids, drugs, hormones, peptides
DNA, miRNA, mRNA, RNA, virus
hemoglobin, cytokines, etc.
Compatible analytical methods include LC-MS, immunochemistry, RT-PCR, sequencing, etc.
While the vast majority of analytical methods can be used with DBS, analysis that requires intact whole cells or measures volatile analytes is incompatible with dried samples.
Search the DBS database for published studies on analysis of DBS samples.
Limitations of current DBS collection methods
Despite significant advantages, cumbersome DBS collection methods have limited routine use for testing and medical research.
For example, current methods require that the blood spotted onto filter paper cards be dried in open air for several hours prior to shipping or storage. This exposes the sample to contamination from circulating air and from exposed surfaces. Additionally, the drying rate can be variable based on ambient humidity; a sample will dry much more quickly in an arid atmosphere (i.e. Arizona) than a humid area (i.e. Amazon). Samples have greater stability with rapid drying and storage in low humidity conditions (McDade, 2007).
Sampling from remote, non-laboratory locations is difficult due to the need for hours of air drying in a protected area and awkward handling with multiple components (i.e. lancets, filter paper cards, drying rack, shipping containers). Additionally, proper application of blood to the filter paper requires training to reduce artifacts due to uneven sample coverage; touching the paper, too large or too small of a drop or too much time between drops can make a sample not suitable for analysis. These difficulties have severely limited the ability of a patient to self-collect a sample from home or any remote location.
Once a DBS sample has arrived at a laboratory for testing, a small punch (3 – 6 mm diameter) is taken from the card, eluted in solvent and analyzed by standard analytical methods. The blood spot must be examined carefully to ensure that the sample punch is taken from a representative area of the spot. Uneven sample coverage due to poor application methods, variable hematocrit levels or chromatography effects can cause variable analytical results.
HemaSpot Products- The next generation for DBS collection
HemaSpot products solve pain points for sample collection with a simple to use device that improves sample quality, reduces contamination and allows immediate shipment. HemaSpot streamlines and simplifies sample collection in contrast to traditional DBS methods (Fig 1).
To learn more about DBS Technology, check out the HemaSpot page.
Fig 1. Comparison of blood collected by traditional DBS and HemaSpot
CDC Presentation on DBS
The Centers for Disease Control (CDC) has created a helpful overview of DBS technology. View the PPT presentation here. DBS_OverviewCDC
De Jesus VR, Zhang XK, Keutzer J, Bodamer O, Mu Al, Orsini J, Caggana M, Vogt R, Hannon WH; Clin Chem 2009, 55:1; 158–164.
Gonza´lez-Gross M et al. on behalf of the HELENA Study Group; International Journal of Obesity 2008, 32: S66–S75.
Mei JV, Alexander JR, Adam BW, Hannon WH; J Nutr.; 2001, 13:1631S-6S.
McDade T, Williams S, and Snodgrass J; Demography 2007, 44: 899–925.
Solomon SS, Solomon S, Rodriguez II, McGarvey ST, Ganesh AK, Thyagarajan SP, Mahajan AP, Mayer KH; Int J STD AIDS 2002, 13:25-8.
Vidal-Taboada, JM et al.; BMC Medical Genetics 2006, 7:451
By vastly simplifying and improving blood sample collection and storage, HemaSpot delivers superior DBS technology for medical research.