Capillary finger-prick blood draws have gained popularity. This is partly in response to innovations in point of care testing and remote sampling. Capillary blood has distinct advantages in hospital labs, clinical labs, and in other circumstances requiring on-site sampling and other more traditional blood collection practices. An ongoing quest to streamline workflows and make them more efficient has led to a reconsideration of dried blood spot sampling.
Capillary blood sampling saves money in clinical trials and clinical testing and research in patient-centric clinical and hospital labs. It is easy to implement and is not disruptive of clinical laboratory workflow. It has strong applications in clinical research, pediatrics, therapeutic drug monitoring (TDM), preclinical experimental animal research, yielding NGS-grade RNA/DNA for molecular research, and many more areas, with even more new applications currently in development.
When compared to traditional wet blood and plasma collection using venipuncture, capillary blood sampling is safer and easier, so much so that nearly anyone can perform the procedure with appropriate, minimal training. However, there are risks associated with the process of finger-stick blood draws. To understand these important safety concerns puts us in a better position to take advantage of this powerful innovation and appreciate its usefulness in science, clinical research, and healthcare at large.
Understand the Risks
Switching to capillary blood collection devices can help us avoid some of the more frightening dangers associated with wet blood sample shipping and storage. However, improper use of capillary blood collection techiques can create hazards of its own. To assume the procedure is totally safe can make us more vulnerable.
Chief among the risks is exposure to bloodborne pathogens, particularly hepatitis B. "In finger-sticks, the blood flowing freely from the site of the puncture exposes both the healthcare worker taking the sample and the environment to blood-borne infectious agents that the patient may have, notes Sharon M. Geaghan, M.D., in an interview with Clinical Lab Pathologist. "Even in an Iraq combat zone, data from an Air Force theater hospital showed that finger sticks were the highest risk activity for occupational exposure to blood and bodily fluids, representing more than 70% of all exposures."
Know What You're Doing
Safety recommendations include choosing the proper equipment (such as an appropriate lancet), knowing the best puncture sites, and following all the correct procedures to ensure not just the safety of all involved, but the integrity of the sample and resultant data.
For those who don't have time to study detailed recommendations in depth, there are more efficient and convenient options.
For those in low-resourced regions, or for patients and participants involved in their own or others' sampling and treatment regimens (to boost adherence, compliance, and subject retention, or to promote convenience, positive patient experience, patient-centric labs, etc.), this is much easier than using dried blood spot cards and filter paper and is the most convenient way to proceed.