How Are Dried Blood Spot Kits Used in Forensics?

Dried blood spot (DBS) technology is increasingly being adopted in forensic science as a reliable and efficient tool for collecting and analyzing blood samples. Originally developed for clinical testing and newborn screening, DBS kits are now finding new relevance in criminal investigations, toxicology, and evidence management.

This article explores how dried blood spot kits are used in forensic settings, from DNA profiling to drug detection, and why they are becoming a valuable tool in modern investigations.

DBS Collection in Forensic Contexts

In forensics, DBS cards are used in two primary ways:

  • Evidence collection: When dried blood is found at a crime scene, samples are typically collected via swabs or substrates – but they can also be transferred to a DBS card for controlled storage and analysis.
  • Reference sampling: Law enforcement or forensic labs can collect blood from suspects or victims via finger prick to obtain DNA or toxicology profiles using standardized DBS kits.

DBS kits typically include a lancet, sterile filter paper card, alcohol swab, and detailed instructions. Once the sample is collected and dried, it is sealed in a tamper-evident pouch and labeled for the chain of custody.

DNA Profiling from Dried Blood Spots

DBS samples preserve nucleated cells, which makes them suitable for DNA extraction and profiling. Even a small disc punched from a dried spot contains enough material for:

  • Short tandem repeat (STR) analysis
  • Y-chromosome or mitochondrial DNA typing
  • Kinship or paternity testing

Because the samples are dried and stable at room temperature, DBS cards provide a safer, more manageable alternative to liquid blood for long-term evidence storage.

Forensic Toxicology Applications

Toxicological analysis from DBS is a growing area of interest. Using techniques like LC-MS/MS, forensic labs can detect and quantify:

  • Drugs of abuse (e.g., cocaine, opioids, amphetamines)
  • Prescription medications
  • Alcohol biomarkers
  • Poisons and toxins

DBS-based toxicology is especially useful in situations where collecting or storing venous blood is impractical, such as in field investigations or postmortem screenings in remote locations. Read our blog post on how dried blood spot cards are used in drug studies if you would like to learn more about the toxicological applications of DBS. 

Benefits for Forensic Investigations

Dried blood spot kits offer several advantages in forensic settings:

  • Portability: Lightweight and easy to use in the field
  • Reduced biohazard risk: Dried samples are less likely to transmit infectious diseases
  • Long-term stability: Can be stored at room temperature without preservatives
  • Minimal sample volume: Only a few drops of blood are needed
  • Chain of custody integrity: Cards can be easily labeled, sealed, and tracked

These benefits make DBS kits ideal for high-throughput casework, cold case archives, and rapid deployment during emergencies or disaster victim identification.

Considerations and Limitations

While DBS has many advantages, it also comes with challenges that forensic labs must address:

  • Sample size limitations: A single spot may not provide enough material for repeat testing
  • Validation required: Assays must be validated for the DBS matrix to ensure accuracy
  • Proper training: Collectors must follow strict protocols to avoid contamination or inadequate samples

Nonetheless, many forensic labs are working to standardize DBS workflows and incorporate them alongside traditional sampling methods.

The Role of RDA Spot in Forensic DBS

RDA Spot designs DBS kits that meet the stringent requirements of forensic applications. Our cards are engineered to preserve sample integrity and support downstream DNA and toxicology analysis. We also provide customized solutions for law enforcement and forensic labs seeking to modernize their sample collection protocols.

A Modern Tool for Modern Investigations

As forensic science continues to evolve, dried blood spot kits offer a practical, scalable alternative to conventional blood sampling. From simplifying evidence collection to enabling drug screening in the field, DBS kits are poised to play an increasingly important role in the future of criminal justice.

References

  1. Niemiec, A. Dried Blood Spot in Toxicology: Current Knowledge. Separations. https://doi.org/10.3390/separations8090145.(2021).
  2.  Chace, D. Lappas, N. The Use of Dried Blood Spots and Stains in Forensic Science. Dried Blood Spots: Applications and Techniques. https://doi.org/10.1002/9781118890837.ch11. (2014).