safety concerns in finger-stick capillary blood sampling

In recent years, capillary finger-stick blood sampling has become more commonly applied in research, decentralized clinical trials, population studies, disease monitoring, toxicology, anti-doping and other industries. This is partly in response to innovations in devices used for point of care testing and remote microsampling.

Capillary blood sampled from a fingertip can have distinct advantages over traditional blood draws from a vein in the arm, including the ability to collect samples at home or in other remote locations – often without assistance from a health professional.

Blood samples collected from a fingertip deliver a dried blood sample, which can be mailed to the lab sealed in a specimen bag that fits inside a standard shipping envelope for sending via regular post. These microsamples will dry during transit and remain stable until analysis in the lab.

Traditional Sampling vs. Finger-Stick Sampling

Traditionally, venous blood is drawn via a needle placed in the arm by a phlebotomist who collects vials of wet blood that are cold shipped to hospital labs and clinical labs for testing. This approach requires people to visit a medical or lab facility for assisted "blood work" sampling with a healthcare professional – an appointment that many of us dread.

While many hospitals and labs are set up for conventional sampling and testing of "wet blood," there is a movement to shift more systems over to dried blood sampling for efficiency, convenience and potential cost savings.

The shift to remote finger-stick microsampling has benefits, including:

• Reduces hospital and lab visits for study volunteers or patients;
• Reduces staffing needs for trained phlebotomists;
• Eliminates expensive cold shipping and storage; and
• Streamlines workflows in both clinical and research labs.

But is finger-stick sampling safe? 

Understand the Risks of Finger-Stick Sampling

Switching to capillary blood collection devices can help us avoid some of the dangers associated with wet blood sample shipping and storage, such as compromised stability of blood samples. However, improper capillary blood collection methods can create hazards as well. To ensure the sample collection process is safe, it is important to understand the potential risks.

Chief among the risks of any blood collection method 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," noted Sharon M. Geaghan, M.D., in an interview with Clinical Lab Pathologist. 

Taking extra precautions to wash the hands before and after sample collection can help mitigate this risk. For the person being sampled, disinfecting the lanced fingertip immediately after sampling and covering it with a bandage is recommended. For the person assisting with finger-stick sampling, wearing gloves and/or washing or disinfecting the hands before and after is advised.

Reap the Benefits of Finger-Stick Sampling

In addition to being more patient-centric than venipuncture, capillary finger-stick blood sampling can save time and money in research, pharmaceutical clinical trials and analysis in clinical and hospital labs.

Microsampling is considered relatively easy to implement without disruption to a laboratory workflow if the lab is set up for processing and analyzing conventional dried blood spot (DBS) filter cards.

In fact, if your lab transitions from using DBS cards to using the hemaPEN^® microsampling device for DBS sampling, you can eliminate the hole-punching step in your lab.

Each hemaPEN device delivers 4 DBS samples on pre-punched filter paper, which is enclosed in a cartridge within the hemaPEN. When processing these DBS samples, the other steps in your DBS workflow remain the same.

As compared to traditional wet blood and plasma collection using venipuncture, capillary blood microsampling with a quick finger-stick is easier. Microsampling solutions like the Mitra^® device with VAMS^® technology are designed so that nearly anyone can perform the procedure with minimal training.

The instructions for use (IFU) and training videos that were created to guide people in correctly using the hemaPEN or Mitra devices include safety measures to help guard against the potential risks associated with any blood draw.

Understanding the safety concerns puts us in a better position to take advantage of this powerful innovation and appreciate its usefulness in clinical settings, remote therapeutic drug monitoring (TDM), and scientific research that includes preclinical animal research, molecular studies, toxicology and other areas, with more applications in development.

Know How to Collect a Finger-Stick Blood Sample

Safety recommendations for finger-stick blood sampling include washing your hands with warm, soapy water and choosing the proper equipment (such as an appropriate lancet), knowing the best puncture sites, and following all the correct procedures to ensure safety, and the integrity of the sample so it can deliver reliable data.

The Mitra device is available in Sample Collection Kits that come with easy-to-use microsampling devices, illustrated instructions, links to video demonstrations, and all the supplies needed to safely collect finger-stick blood samples.

Customized sample collection kits from Neoteryx, the microsampling product brand of Trajan Scientific and Medical, come with detailed, simple instructions that almost anyone can follow to collect blood samples anywhere, anytime.

For those working in the field in low-resourced regions, using remote microsampling devices that are based on volumetric absorptive microsampling is much easier than using dried blood spot (DBS) cards and filter paper.

One reason is that a sampling device based on VAMS technology has an absorptive tip that will collect the exact sample volume needed for accurate analysis. There is no second-guessing or struggling to land a blood drop within a tiny circle on a DBS filter card, and no need to air dry the samples before shipping.

Just touch the VAMS tips of the Mitra device to the drop of blood on your finger until filled. Close up the device immediately after sampling. Place the sampled device inside the specimen bag, and place that in a standard shipping envelope for mailing to a central lab. The samples dry during transit, thanks to a packet of drying desiccant inside the specimen bag. No cold storage or cold shipping is necessary.

For more information on how Neoteryx microsampling products from Trajan help researchers, visit our Technical Resource Library.

Image credits: Trajan, Neoteryx