preservation of biological specimens: protocols, best practices, and opportunities for improvement

Biological specimens like blood, saliva, and tissue play a crucial role in diagnostics, research, and disease surveillance. To ensure the quality and reliability of these samples, it is important to follow strict protocols for their preservation. Proper storage and handling are essential to prevent degradation, contamination, or compromised results.

• Human physiology before the biospecimen collection - Biospecimen quality may be affected by overall health and the medication status of the patient/research participant, food and beverages consumed, as well as circadian rhythms. 
  
  As a golden rule of best practices, pre-analytical variables must be notated for reference if they cannot be controlled; information about these factors should be collected and recorded to decrease the variability between samples.

• Collection practices - Preservation of the biospecimen as quickly as possible after removal from the patient is one of the key best practices during sample collection.
  
  It is also vital to annotate each specimen with the conditions of biospecimen collection, processing, and storage, according to Biospecimen Reporting for Improved Study Quality (BRISQ) or a similar collection of recommendations.

• Handling practices before downstream testing - Best practices also dictate optimization of biospecimen handling to minimize molecular changes that may result from the processing activities.
  
  Most critical factors in this stage include cold ischemia time (the time between biospecimen removal from the patient and its placing into fixative), temperature and timing of bioprocessing, the size and volume of the sample, as well as freeze-thaw cycles.

Protocols for Biological Specimen Preservation

When it comes to storing and handling biological specimens, protocols can vary based on the type of sample and the intended analysis. However, several core principles apply to most sample types:

1. Timely Processing: Delays in processing can lead to the breakdown of nucleic acids and proteins, rendering samples unusable for further analysis.
2. Appropriate Temperature Control: Depending on the analyte of interest, specimens should be stored at room temperature, refrigerated (2°C–8°C), frozen (-20°C to -80°C), or cryopreserved in liquid nitrogen (-196°C).
3. Use of Preservatives: Chemical preservatives or stabilizers may be added to the sample at the time of collection to inhibit enzymatic degradation and microbial growth.
4. Minimal Freeze-Thaw Cycles: Repeated freezing and thawing can damage sensitive biomolecules. Samples should be aliquoted to avoid unnecessary thawing.
   
   

Best Practices for Biological Specimen Storage and Handling

To maintain the integrity of biological samples, several best practices must be followed, in addition to strict temperature regulation and time-sensitive handling:

• Labeling and Tracking: Each specimen should be clearly labeled and linked to its corresponding metadata, which includes the subject ID, date and time of collection, and the method of collection.
• Secure Storage: Specimens must be stored in appropriate containers, such as cryovials or sealed plastic tubes, and kept in properly monitored storage units. This helps prevent exposure to fluctuating environmental conditions.
• Routine Equipment Calibration: Freezers and refrigerators used for specimen storage should be regularly calibrated and monitored to ensure consistent operation.
• Sample Transport Compliance: When transporting biological specimens, the packaging and labeling must adhere to local and international regulatory requirements, especially for samples classified as infectious.

Additionally, laboratories can implement inventory management software to track specimen usage and location, which helps minimize the risk of loss or mishandling.

How Can Institutions Improve?

To aid with advancements in best practices related to biospecimens, programs such as the NCI’s Biospecimen Research Network and the Standardization and improvement of generic pre-analytical tools and procedures for In-vitro Diagnostics (SPIDIA) in EU are conducting original research to identify and address the major questions of biospecimen methodology before biospecimen testing.

According to these findings, organizations should establish sample lifecycle management strategies that dictate how samples are collected, transported, processed, stored, documented and even archived for future use.

Advances in medical science are most often derived from properly preserved biological samples and the clinical data linked to them. Preservation of biological specimens throughout their sample cycle is thus at the forefront of medical research.

Learn more about microsampling to collect blood samples and other biological specimens for research and healthcare here:

Additionally, laboratories can implement inventory management software to track specimen usage and location, which helps minimize the risk of loss or mishandling.

Improving Specimen Integrity with Microsampling Techniques

Microsampling methods, such as Volumetric Absorptive Microsampling (VAMS®), are becoming increasingly popular due to their simplified logistics and excellent preservation characteristics. These devices collect small, fixed volumes of blood that dry quickly and can be shipped and stored at room temperature.

Dried blood microsamples greatly reduce the risks associated with improper freezing or temperature fluctuations during transport. As a result, they are ideal for remote studies, global research collaborations, and field-based diagnostics.

When used correctly, microsampling can maintain and even enhance the standards of biological specimen storage and handling. Given that new studies continue to validate the effectiveness of dried sample formats, more laboratories are incorporating these tools into their workflows.

Final Thoughts

Maintaining the quality of biological specimens is crucial for producing accurate scientific and clinical data. By following established protocols for the preservation of biological specimens and adopting best practices for their storage and handling, researchers and healthcare professionals can minimize variability and ensure reliable test results.

Modern techniques, such as microsampling, are improving the accessibility and effectiveness of specimen management in both centralized laboratories and decentralized settings. With a continued emphasis on quality and consistency, the future of specimen preservation appears to be increasingly efficient and sustainable.

Image Credits: Shutterstock, Trajan, Neoteryx