A Smarter Alternative to Venous Blood Draws

Blood sampling has long been vital to medical diagnosis, from ancient bloodletting rituals to modern venipuncture techniques. Early physicians in Egypt, Greece, and Rome believed that removing blood could help rebalance the body's "humors."

This practice continued into the 19th century, even as evidence-based medicine began to take shape!

Today, we still recognize the importance of blood in understanding the body's internal functions, but now we aim to analyze this life-sustaining fluid rather than deplete it.

Modern Venipuncture: The Gold Standard at a Cost

What Is Venipuncture?
Venipuncture is the process of inserting a needle into a vein, typically the medial cubital vein located at the elbow, to collect blood for laboratory testing. It offers several advantages, including:

• Volume: The ability to collect larger blood samples ensures that repeat testing can be conducted.
• Versatility: It provides access to cells, plasma, and serum.
• Reliability: Venipuncture is supported by well-established workflows and protocols.

Limitations of Wet Blood Draws

1. Invasiveness and Discomfort: Many patients experience needle anxiety and may be concerned about potential bruising, which can deter them from blood draws.
2. Logistics and Cost: Whole blood must be stored at a temperature of 2–8 °C and used within seven days. This requirement necessitates the use of dry ice, special packaging, and expensive courier services, raising overall costs.
3. Accessibility: Patients who are remote or homebound often face challenges related to long travel distances and scheduling appointments for blood draws.
   
   

The Blood Sample Journey: From Draw to Data

Collection & Labeling: Venous blood samples are drawn by trained phlebotomists, labeled—often with barcodes—and entered into tracking systems to ensure accurate patient-to-data matching.

Transport & Storage: Samples are transported as hazardous, refrigerated shipments. Any lapse in temperature can render them unusable.

Processing & Analysis: Blood samples may be centrifuged to separate plasma or serum, or they may be directly analyzed, depending on the specific test.

Results & Communication: Advancements in technology have shortened the turnaround time for results to just a few days. However, each step still requires strict temperature and time controls to maintain sample integrity.

Less Invasive Alternatives: The Microsampling Revolution

Recent advancements in analytical instrumentation and microsampling techniques have led to the development of capillary blood collection methods that reduce invasiveness and logistical challenges. When comparing capillary blood collection devices to traditional venipuncture for medical and laboratory use, the advantages in terms of comfort, cost, and accessibility are significant.

Dried Blood Spots (DBS)  
Method: Blood is collected via a finger or heel stick and dropped onto filter paper.  

Pros: No requirement for a cold chain, allows for remote self-sampling, and has decades of neonatal screening data.  
Cons: Hematocrit bias, uneven distribution of analytes, and a risk of contamination during manual punching.

Pre-Cut Dried Blood Spots (PCDBS)  
Method: Blood is collected via a finger stick onto a fixed-volume card with layers that effectively separate plasma from cells.  

Pros: Reduces hematocrit impact and ensures consistent sample volume.
Cons: Requires a trained technician for accurate volume deposition.

Dried Plasma Spots (DPS)
Method: Fingerstick blood sample is collected onto a multi-layer card, then peeled to isolate plasma.  

Pros: Overcomes hematocrit variability and retains the logistics advantages of DBS.
Cons: Not suitable when whole blood is necessary.

Volumetric Absorptive Microsampling (VAMS®)  
Method: Fingerstick blood sample onto a Mitra® device (10–30 μL tips) that quickly absorbs a fixed volume of blood.  

Pros: Hematocrit-independent, precise volumetric collection, quantitative analysis, self-administered, no special handling required. 
Cons: Single use only.

Practical Benefits Across Various Contexts

Patient Comfort and Compliance: Fingerstick blood sampling is a less invasive alternative to needles, which helps reduce anxiety and bruising. This method is particularly beneficial for ongoing monitoring of sensitive populations.

Remote and Decentralized Studies: Self-sampling kits allow participants to collect samples from anywhere, broadening the reach and diversity of clinical trials.

Cost and Logistics: This approach eliminates the need for refrigeration, dry ice, and hazardous material shipping, significantly reducing operational costs.

Ethical Advantages in Animal Research: The low volume of samples required for VAMS (Volumetric Absorptive Microsampling) reduces the number of animals needed in preclinical toxicology and pharmacokinetics studies.

Embracing The Future of Blood Sampling

The evolution of blood sampling has advanced from ancient bloodletting to needle-based venipuncture, and now to capillary microsampling. This progression reflects the medical community's ongoing quest for more precise, humane, and cost-effective diagnostic methods.

By comparing the performance and advantages of capillary blood collection devices to traditional venipuncture for medical and laboratory use, researchers and clinicians are uncovering new opportunities.

These include broader participant access, richer longitudinal data, and more efficient workflows. As microsampling technologies continue to develop, they promise to make blood-based insights more inclusive—and ultimately, more actionable—than ever before.