collecting a specimen sample: 3 methods examined

Collecting blood samples and other biological specimens is crucial to the understanding, prevention, and treatment of disease. However, from the patient’s perspective, it can also be painful, unnerving, frightening, and inconvenient. 

What blood taking technique is used depends at least in part on the nature of the condition being tested for, but most commonly involves inserting a needle into a vein, referred to as a "venipuncture" blood draw. Usually, medical practitioners will draw venipuncture blood samples in their clinic offices or labs, at times convenient for them (if not always for patients).

What Are Some Popular Types of Sample Collection Methods Used Today?

Three popular methods of blood collection or sampling are:

1. Arterial Sampling
2. Venipuncture Sampling
3. Fingerstick Sampling

Arterial Sampling

This blood withdrawal technique most commonly takes place in a hospital environment. It is used to identify metabolic, respiratory, and mixed acid-base disorders where CO2 levels require understanding or monitoring.

While generally safe, the procedure can be upsetting and painful for the patient. In addition, several potential contradictions can affect the collection site, such as an abnormal modified Allen test or local infection. There is also an increased risk of bleeding complications in patients with coagulopathy.

Venipuncture Sampling

Venipuncture is the most common way to collect blood from adult study participants or patients. Collection takes place from a superficial vein in the upper limb, generally the median cubital vein in the arm; this vein is close to the skin and does not have many large nerves positioned nearby, which reduces pain and discomfort for the patient.

Venipuncture can occur in a general medical practitioner’s office and is often carried out by a trained phlebotomist or nurse. However, its commonality does not equate with it being the best way to collect a blood sample. Many patients find it inconvenient and stressful. Because this approach involves collecting liquid blood in a tube, there are also risks related to the storage, transportation, and potential loss or contamination of the samples once they are collected. These same concerns also affect the suitability of arterial sampling.

Fingerstick Sampling

Fingerstick or finger-prick sampling involves taking a minimal amount of blood from the patient, usually from the fingertip. Fingerstick sampling is over quickly and requires very little preparation, which helps to reduce stress and anxiety in patients, particularly in children and nervous adults.

Patient comfort and welfare at the point of collection is not the only reason this method should be considered the best way to collect a sample. This type of sampling takes only a few drops of blood to produce a "microsample." The long-term benefits of microsampling to the patient include the loss of less blood and the ability to carry out testing at home. Since fingerstick sampling is easy to do, a phlebotomist is not required for the procedure.

A blood sample collection procedure using a finger-prick with a lancet and a portable microsampling device, such as a Mitra^® device or a hemaPEN^® can be done by virtually anyone, anywhere.

Because finger-prick sampling can be done at home, work or in other locations, it supports a host of remote research studies, like decentralized clinical trials, and remote monitoring of patients who take therapeutic drugs.

In many cases, a healthcare professional can assist with collecting the microsamples and/or provide study subjects with an initial orientation on correct self-sampling with these devices.

Finger-stick sampling is designed to deliver a small, dried blood sample rather than a liquid (wet) blood sample. The data derived from dried samples typically correlates to the data derived from wet samples. Dried blood sampling can replace conventional sampling in many scenarios.

Further, since dried blood specimens don't require cold shipping, they have the advantage of being easier and cheaper to transport to a laboratory for analysis.

Arterial and venipuncture blood withdrawal techniques are still widely used, and still have their places in medicine, clinical research, and patient care. However, with advances in technology and a greater understanding of dried blood sampling, fingerstick collection is gaining ground.

Microsampling devices from Neoteryx, the microsampling brand of Trajan Scientific and Medical, continue to advance specimen collection. These devices, which can be paired with Trajan's sample processing or sample analysis solutions, enable sample ID tracking using a barcode system. The barcoding makes any mix-up or loss of samples less likely.

Technological advances in dried sampling also mean reduced contamination risks and reduced sample rejection rates, both of which help to reduce costs.

From preclinical research to clinical trials to remote therapeutic drug monitoring, the future of microsampling is here! To learn more about how others are using microsampling in their work, visit our online Industry Applications page.