Thanks to the development of at-home blood sample collection kits, consumers today have access to a large number of health tests that they can take without ever having to leave home. With one-click shopping, a simple fingerstick, and a mailbox, consumers can conveniently get health insights that previously required a visit to the clinic or lab for a blood draw.

However, we have only scratched the surface of what is possible with at-home blood testing.

 

The advantages and disadvantages of dried blood spot kits

Most at-home blood sample collection kits utilize dried blood spots (DBS), in which users apply fingerstick blood to a filter paper or card that dries the whole blood in a fibrous matrix. Once dried the paper is then returned to the lab for analysis. While the gold standard in blood testing remains testing liquid samples (typically liquid plasma or serum separated from blood cells via centrifugation), DBS kits have made decentralized and at-home testing possible for many analytes.

DBS kits have many advantages for at-home self-collection. DBS devices are overall pretty simple to use; users simply need to apply several drops of blood from a fingerstick onto the DBS paper and allow the sample to dry before shipping. Shipping and storing DBS samples is simple too as the samples can be shipped with a small, lightweight package without temperature regulation. The samples are also generally stable for many days if not weeks. Lastly, DBS papers and cards are relatively inexpensive to manufacture, making at-home collections more economical for payors and patients.

Despite these advantages, DBS kits also has several limitations that inhibit broader use. To analyze DBS samples, labs need to “punch” out blood spots from the paper, then elute those spots into a liquid solvent to extract the target analytes from the paper. This process can take several hours, and the elution steps dilutes the sample by as much as 10- to 15-fold which often reduces the concentration of the target analyte below the measurement capabilities of lab analyzers (many of which are designed to test undiluted blood specimens). Because of this limitation, the majority of DBS samples are tested with mass spectrometry instead of clinical analyzers, which further limits the number of compatible assays and requires equipment not typically used in clinical laboratories. Lastly, DBS papers often suffer from an effect called “hematocrit bias”, in which the amount of blood sample collected depends on the patient’s hematocrit (the percentage of the blood composed of blood cells). Hematocrit bias leads to inconsistent blood volumes, and thus inaccuracies in the end result.

Because of these limitations with DBS kits, new kits and devices are needed to enable at-home collection options for the majority of clinical blood tests.

 

How to collect liquid plasma and serum samples at home

Sandstone’s Torq technology uniquely merges the sample prep advantages of centrifugation (the gold standard for plasma and serum analysis) with the convenience and ease-of-use of an at-home collection kit. Whereas most centrifuges are confined to the lab, Torq puts the centrifuge in the home to provide quick, simple, and high-quality separations of plasma or serum from whole blood.

With Torq kits, labs receive stable, liquid plasma or serum samples free of hemolysis and ready to be tested without further dilution. This capability removes the need for specialized lab equipment (the labs can use the clinical analyzers regularly used for routine blood work), and makes possible new at-home tests including electrolytes, metabolites, liver markers, lipids, cardiac markers, cancer markers, DNA/RNA markers, among others that would otherwise require blood draws at the clinic or lab.

Visit our shop or contact us below to learn more about how Torq can be integrated into your blood sample collection workflow.

 

References

  1. Zakaria R, Allen KJ, Koplin JJ, Roche P, Greaves RF. Advantages and Challenges of Dried Blood Spot Analysis by Mass Spectrometry Across the Total Testing Process. EJIFCC. 2016;27(4):288-317. Published 2016 Dec 1.
  2. H. Chace, V.R. De Jesus, A.R. Spitzer, Clinical chemistry and dried blood spots: increasing laboratory utilization by improved understanding of quantitative challenges, Bioanalysis 6 (2014) 2791–2794.
  3. Vaishali Londhe, Madhura Rajadhyaksha. Opportunities and obstacles for microsampling techniques in bioanalysis: Special focus on DBS and VAMS, Journal of Pharmaceutical and Biomedical Analysis, Volume 182, 2020, 113102

Contact us today to learn more about Torq's fingerstick blood collection products: