For the most accurate diagnosis, it’s important to think beyond specimen collection and consider the journey your viral sample takes to the laboratory. Ensuring viability during this transport time is more critical than ever as laboratories manage higher testing demand. 

• Viruses should be adequately protected
• Rapid transportation to the laboratory under the proper conditions can greatly enhance effective isolation
• All specimens should be stored in sterile containers and refrigerated immediately upon collection.
• Ship/transport with enough ice packs sufficient to maintain an approximate 4ºC environment.
• NEVER send dry swabs.
• Viruses should be transported to the laboratory in the appropriate transport medium called viral transport medium

What is viral transport media?

• A viral Transport Medium (VTM) is a solution that allows for the safe transfer of viral samples to a laboratory for analysis.
• In many cases, this is a liquid that creates a balanced buffer solution for maintaining a neutral pH, antimicrobial agents, a source of protein, and sucrose that serves as a preservative.
• Without ultra-low temperature storage or appropriate viral transport media, many viral specimens will begin to degrade rapidly. This increases the risk of a false-negative result during analysis at the laboratory.

What are the components of viral transport media?

1. Viral transport tube

Viral transport media is included in a sterile tube typically made of premium medical-grade plastic. Some tubes may be formulated to contain buffered proteins and antibiotics that suppress the growth of potentially contaminating bacteria and fungi.

2. Viral transport cap

A securely closed transport tube is critical for protecting the sample specimen from contamination during transport. Many tubes feature screw caps designed for secure closure and ease of use, while other transport tubes may feature a plug top for a secure seal.

3. Collection swab

Some viral transport media and transport systems are formulated to work with a specific type of swab. Not all swab materials are suitable for viral testing. For example, nasopharyngeal swabs cannot be made with cotton as organic materials interfere with the polymerase chain reaction (PCR) testing process. Some manufacturers sell swab kits that include viral transport systems, to eliminate any confusion around the right components.

Common viral transport media

Viral transport media is used for the preservation of a wide range of viral specimens, including infections that are difficult to diagnose on the spot and instances where knowing a specific viral strain can support diagnosis or population health efforts.

Some of the most common viral transport products include:

• Universal transport media (UTM) may be used to transfer samples to laboratories for use in viral antigen detection tests, PCR, and rapid tests. These tubes may contain antimicrobial agents to minimize bacterial and fungal contamination, as well as glass beads that assist in releasing and dispersing the sample into the medium during laboratory vortexing.
• Liquid amies transport systems are typically used for the collection and transport of bacteria to be processed in bacterial culture, rapid tests, gram staining, automation, and molecular testing. Amies liquid medium is a balanced salt solution that works to maintain the viability of aerobic, anaerobic, and fastidious bacteria during transport to the laboratory.
• Molecular preservative provides total microbial inactivation, simplifying specimen collection and preservation specifically for molecular research. This transport media is compatible with the preservation of DNA/RNA from bacteria, viruses, and tissues and provides nucleic acid stability at ambient temperatures for up to 30 days.
• Dry transport tubes are emerging as perhaps the most convenient way to collect and transport specimens from the patient/animal to the laboratory. These transport tubes do not use a viral transport media but offer a sterile environment for rapid transport.

Temperature for storage of specimens

Specimens can be stored at 2 to 8°C for up to 72 hours after collection. If a delay in testing or shipping is expected, store specimens at -80°C or lower. Extracted nucleic acid should be stored at -80°C or lower. Long-term storage should be done at -80°C or using Liquid Nitrogen ( -196°C).