Viral Transport Medium: An Overview with Product Examples

The accuracy of a medical diagnosis begins with two key components: the right tool for collecting an ample amount of a viral sample and careful storage of that material as it is transferred to a laboratory for analysis. Viral samples can rapidly decay if not stored appropriately during transport. This is why it’s vital to select the right viral transport media.

Below we’ll define viral transport medium and when it is used, explain the typical components and options, as well as the average price range for viral transport media.

What is viral transport medium?

Viral transport medium 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 medium?

A viral transport system depends upon more than the viral transport media solution. In fact, there’s growing evidence that dry transport tubes can also be highly effective in maintaining viable samples during transport. As a result, a successful viral transport system depends upon the effectiveness of a number of key components.

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 medium uses

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. Common viral transport media uses include:

1.Influenza virus: Universal viral transport media help maintain viral respiratory swab sample viability at room temperature for a number of days, allowing for health experts to diagnose specific strains of influenza.

2.SARS-CoV-2: According to the FDA not all transport media are compatible with SARS-CoV-2 testing platforms, as there is a risk of exposure to harmful cyanide gas. This gas is a byproduct of a reaction between specific chemicals used in some transport media and the sodium hypochlorite used in some SARS-CoV2 testing platforms or laboratory processes. As a result, it is important to select viral transport media cited for use in coronavirus testing or approved for this use by the FDA.

3.Enterovirus D68: This non-polio enterovirus has proven to be challenging to test for because on-the-spot tests cannot always perform the analysis necessary to attribute the virus to a particular strain of enterovirus or altogether different respiratory illnesses.Viral transport medium product examples

There are a number of different virtual transport medium products to meet the needs and price considerations.Selecting the right viral transport medium depends upon the type of sample you’re transporting. Some of the most common viral transport products include:

• Universal transport medium may be used to transfer samples to laboratories for use in viral antigen detection test, 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 preservation of DNA/RNA from bacteria, viruses, and tissues and provides nucleic acid stability at ambient temperatures up to 30 days.
• Dry transport tubes are emerging as perhaps the most convenient way to collect and transport specimens from the patient to the laboratory. These transport tubes do not use a viral transport media, but offer a sterile environment for rapid transport. Injection molded cap ensure a precision fit, eliminating the potential for foreign adhesives to interfere with the specimen. The tubes hold a swab in a round-bottom tube made from virgin polypropylene resin. They may be suitable for use with foam, flocked, cotton, rayon, and polyester swabs.