Dried Blood Spot Cards and More: Why Card Selection Matters

As dried sampling technologies continue to expand across at-home diagnostics, clinical research, and decentralized healthcare, one thing is becoming increasingly clear: not all sampling cards are created equal.

From Dried Blood Spot (DBS) to Dried Urine Spot (DUS) and Dried Saliva Spot (DSS), the performance of a diagnostic test depends not only on the analytical method—but also on the card used to collect, stabilize, and preserve the sample.

At the center of this decision lies a critical factor: the biomarker itself.

What Are Dried Blood Spot Cards or Dried Technology Cards?

Dried technology cards are engineered absorbent substrates designed to collect, store, and transport biological samples in a dried format. Companies like Ash use them as a fast, economical, and easy-to-use at-home testing solution. 

These cards are far more than simple paper. They are developed to:

• Control sample absorption and spreading
• Preserve analytes during drying and transport
• Ensure consistency across analytical workflows

Ash partners with leading material innovator, Ahlstrom and EBF, to leverage their broad portfolio of specimen collection cards, designed for different screening and research applications.

Why Card Selection Matters

In dried sampling, the card is not a passive support—it is an active component of the analytical system.

Choosing the wrong card can lead to:

• Inconsistent sample volumes
• Uneven analyte distribution
• Reduced biomarker stability
• Variability in laboratory results

From a patient perspective, this may result in repeat sampling, delays, or reduced trust in at-home diagnostics.

The Role of the Biomarker

The most important factor in card selection is the type and stability of the biomarker being measured.

Different biomarkers behave differently:

• Small molecules: generally stable but sensitive to contamination
• Lipids: highly prone to oxidation
• Proteins: sensitive to degradation and denaturation
• DNA/RNA: extremely fragile and environment-sensitive

This means that no single material can optimally serve all biomarker classes. The biomarker defines the card requirements—not the other way around.

Chemically Treated vs Untreated Cards

To address these challenges, dried sampling cards are generally divided into two complementary approaches.

Untreated (Pure) Cards

Untreated cards are designed for maximum analytical neutrality, with no active chemical additives. These cards are best suited for small molecules, proteins, and general screening applications requiring clean baselines. The cards ensure:

• Minimal analytical background interference
• High compatibility with mass spectrometry and general assays
• Broad applicability across biomarker types

Chemically Treated Cards

Chemically treated cards are engineered for active biomarker stabilization, using embedded reagents to preserve unstable analytes. These cards enable reliable analysis of highly sensitive or unstable biomarkers and are designed to:

• Prevent oxidation of fatty acids and preserve lipid integrity over time
• Support long-term DNA stabilization at ambient temperature
• Handle specialized RNA stabilization formats designed to reduce degradation of nucleic acids during drying and storage

Functional Untreated Platforms: Engineering Beyond Chemistry

Alongside these categories, the dried sampling ecosystem also includes a third group: functional untreated card platforms

These solutions do not rely on embedded chemical stabilizers, but instead use material engineering and physical design to support molecular workflows where handling and process control are critical. Untreated substrates are optimized for RNA workflows by using ultra-pure fiber compositions, minimizing enzymatic contamination risk, and controlling absorption behavior for faster stabilization.

Plasma Separation Cards

Plasma separation cards are designed to enable passive plasma separation from whole blood, which provides a cleaner plasma matrix without chemical intervention.

They rely on:

• Capillary flow dynamics
• Filtration properties of the substrate
• Physical separation of cellular components

Automated Workflow Cards

Automation-ready formats are designed for integration into high-throughput laboratory workflows. These cards are made to work with automatic or semiautomatic equipment to handle high sample volumes. They enable scalable, industrialized screening processing. Key design features include:

• Standardized spotting geometry
• Mechanical robustness for robotic handling
• High reproducibility for automated punching systems

One Card Does Not Fit All

Each category serves a different function:

• Untreated cards → analytical neutrality
• Chemically treated cards → biomarker stabilization
• Functional platforms → workflow optimization

Using a single universal card introduces compromise:

• Loss of biomarker integrity
• Reduced analytical performance
• Limited scalability across applications

Dried sampling technologies are transforming diagnostics – but their effectiveness depends on the core principle: the biomarker defines the requirement, the card defines the outcome. Ash supports its clients in navigating this complexity, identifying the most appropriate card and developing the right kit for their program goals.

Get in touch with Ash if you’d like to scale your gap closure programs or offer testing at-home to your population.

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