Clinics know that proper specimen collection and transport are critical steps in ensuring accurate diagnosis and effective treatment of bacterial infections. 

That’s why it’s essential that your transport medium preserves the viability of microorganisms all the way from the point of collection to the laboratory. 

Liquid Amies transport medium is a trusted solution for maintaining bacterial integrity during transit. It is especially valuable for laboratories that may experience delays in processing samples.

In this article, we will explore what Liquid Amies is, how Puritan® Opti-Swab® Liquid Amies Collection and Transport System enhances its performance, and why this combination is a reliable choice for healthcare professionals seeking accurate and efficient laboratory results.

What is Liquid Amies?

Liquid Amies is a phosphate-buffered, non-nutritive transport medium solution designed to preserve the viability of a wide range of bacteria, including aerobes, anaerobes, and fastidious organisms. 

DID YOU KNOW? Liquid Amies was originally developed to support the safe and effective transport of clinical specimens from the collection site to the laboratory.

Labs all over the world rely on Liquid Amies to make sure that collected specimens remain viable and can be accurately analyzed. Especially if there is a delay between collection and processing. This reliability is crucial for timely and precise diagnosis.

What is in Liquid Amies?

Liquid Amies contains sodium thioglycolate, which creates a reduced environment that maintains the viability of oxygen-sensitive bacteria. The inclusion of chloride salts helps balance the osmotic pressure, preventing damage to bacterial cells during transport. 

The formulation of Liquid Amies medium has become the gold standard in clinical microbiology because it supports the recovery of important pathogens, such as Neisseria gonorrhoeae, which can be particularly fragile in transit.

This chart shows the approximate modified liquid Amies formulation per liter.

The Components of a Liquid Amies Collection and Transport System

Puritan’s Opti-Swab® Liquid Amies Collection and Transport System combines the proven performance of Liquid Amies medium with a uniquely designed HydraFlock® swab for optimal specimen collection. 

Each kit includes a sterile, pre-labeled polypropylene vial containing 1 ml of Liquid Amies medium, along with a scored HydraFlock® swab designed to break easily at a designated point after sample collection.

The HydraFlock® swab features multiple split polyester fibers that allow for superior absorption and rapid release of collected specimens. The swab design ensures that an ample sample is absorbed during collection and released efficiently into the transport medium for accurate testing. Clinics will benefit from the variety of swab types offered that includes standard, mini-tip, and ultrafine configurations. Different swabs are suitable for various sample sites, including the nose, throat, wound sites, and more. We’ll cover the different swab types later in this article.

The secure, self-centering screw cap on the vial captures the swab handle securely, preventing leakage or contamination during transport. This thoughtful design simplifies the collection process while reducing the risk of specimen loss or compromise.

The Benefits of Liquid Amies Transport Systems

Liquid Amies medium offers several advantages that make it a top choice for transporting clinical specimens. 

The most important feature is its ability to preserve bacterial viability for up to 48 hours, allowing laboratories to process specimens effectively even if there is a delay in delivery. (For certain bacteria like Neisseria gonorrhoeae, which are particularly sensitive, it’s recommended to process specimens within 24 hours for optimal results.)

The Puritan Opti-Swab® Liquid Amies Collection and Transport System supports a variety of specimen types, including nasal, throat, vaginal, and wound samples. 

Looking for other uses of Puritan Opti-Swab®? Check out our complete guide to fecal swab test kits.

Clinics love Liquid Amies because they can rely on a single, consistent system for diverse diagnostic needs.

Another advantage of Liquid Amies medium is its compatibility with both manual and automated laboratory processing methods. Specimens collected in the field can be easily integrated into standard laboratory workflows, regardless of the testing platform.

The medium is formulated to maintain the correct osmotic balance and minimizes bacterial cell stress, which is critical for preserving the integrity of the sample until it reaches the laboratory. 

These features combine to make Liquid Amies a go-to tool for accurate and timely bacterial diagnosis.

How to Collect, Store, and Transport a Specimen with Liquid Amies

Proper specimen collection and handling are essential for ensuring accurate diagnostics. Remember: Always follow the package insert for the most up-to-date collection steps. 

If you’re using the Puritan Opti-Swab® Liquid Amies Collection and Transport System, you can follow these steps: 

Step 1: Gather Supplies

Open the sterile pouch by peeling it from the side marked with the arrow. Remove the swab and vial from the pouch, making sure to maintain sterility.

Step 2: Collect the Specimen

Use the HydraFlock® swab to collect the specimen from the patient (e.g., nose, throat, wound site).

Avoid touching any surfaces or areas below the colored breakpoint on the swab to prevent contamination.

Step 3: Insert the Swab into the Vial

Using aseptic technique, carefully remove the vial cap. Insert the swab into the vial containing the Liquid Amies medium.

Step 4: Break the Swab Shaft

Gently bend the swab at the printed breakpoint until it snaps. Then, properly discard the broken handle portion.

Step 5: Secure the Sample

Replace the vial cap and screw it on tightly to capture the swab handle and secure the sample to prevent leaks.

Step 6: Label the Specimen

Record the patient information in the space provided on the vial label to ensure proper identification.

Step 7: Transport the Specimen

Deliver the specimen to the laboratory for processing as soon as possible (ideally within two hours). If immediate processing is not possible, store the specimen at 2–25°C and process within 48 hours (within 24 hours for Neisseria gonorrhoeae).

Additional Tips:

Always wear appropriate personal protective equipment (PPE) and follow laboratory safety protocols. 

And, avoid exposing the specimen to extreme temperatures or direct sunlight during storage and transport.

Liquid Amies FAQs

What is Liquid Amies used for?

Liquid Amies medium is used to transport clinical specimens from the point of collection to the laboratory while preserving the viability of aerobic, anaerobic, and fastidious bacteria.

How long can specimens be stored in Liquid Amies?

Specimens collected using the Opti-Swab® Liquid Amies Collection and Transport System should be transported to the laboratory within two hours. If immediate delivery is not possible, specimens can be stored at 2–25°C and processed within 48 hours. For Neisseria gonorrhoeae, processing should occur within 24 hours.

Liquid Amies vs gel amies, what’s the difference?

While both are used to transport bacterial specimens, Liquid Amies and Gel Amies differ significantly in lab efficiency and testing flexibility. Liquid Amies, like the solution used in Puritan’s Opti-Swab® system, is compatible with many automated platforms, helping reduce manual labor and streamline workflows. Because each vial contains 1 ml of medium, it allows for multiple tests, up to 10 identical inoculations from a single collection. This is ideal for labs performing culture, staining, and validated molecular assays like PCR.

Gel-based systems, on the other hand, are more limited. They typically support only one test per collection. After initial streaking and incubation, additional plating may be needed to isolate or identify organisms, which can extend turnaround time. Gel formats also aren’t typically compatible with molecular testing.

For labs looking for greater flexibility, automation readiness, and streamlined processing, Liquid Amies can provide an operational advantage.

What are the advantages of using Puritan’s Opti-Swab® Liquid Amies system?

This system combines a high-quality Liquid Amies medium with a HydraFlock® swab that ensures optimal absorption and release of specimens. Its self-centering screw cap secures the swab in the vial, minimizing contamination and leakage. The system is easy to use, compatible with both manual and automated laboratory processing, and meets CLSI M40-A2 standards.

Is the system suitable for all types of specimens?

Yes, the Opti-Swab® Liquid Amies Collection and Transport System is versatile and can be used for collecting nasal, throat, wound, vaginal, rectal, and other clinical specimens. Different swab configurations (standard, mini-tip, and ultrafine) are available to accommodate various collection sites.

What precautions should be taken when using the system?

Always use aseptic techniques and wear appropriate personal protective equipment (PPE). Clinical specimens are considered biohazardous and should be handled with care. Never use the system beyond its expiration date, and do not use it if the sterile pouch is damaged.

Does the system support Gram staining and direct microscopy?

Yes. After vortexing the swab in the medium, a portion of the specimen can be placed on a slide for Gram staining and direct microscopic examination, which helps with initial diagnosis.

Can this system be used with rapid diagnostic tests or molecular assays?

Yes, but it is important to validate the system with your specific diagnostic test or platform before use to ensure compatibility.

Does the Opti-Swab® system help prevent bacterial overgrowth?

Yes. Performance studies show that the system maintains bacterial viability while preventing overgrowth when stored at recommended temperatures.

Is the system suitable for transporting viruses, mycoplasmas, or ureaplasmas?

No. The Liquid Amies system is intended for bacteria. For transporting viruses or other organisms, specialized transport media are required. 

Related Articles:
How to do a MRSA Nasal Swab
How to Choose the Right Transport Media
Puritan Liquid Amies Compatible with Copan’s WASP®

Why Choose Puritan Opti-Swab®?

When it comes to collecting and transporting clinical specimens, reliability matters. The Puritan Opti-Swab® Liquid Amies Collection and Transport System stands out because it’s thoughtfully engineered to support both healthcare providers and laboratory professionals in obtaining accurate, timely results.

Each component of the system is designed for ease of use and optimal performance. The HydraFlock® swab provides superior specimen uptake and release, while the color-coded, pre-scored shaft ensures safe and simple sample transfer into the vial. 

Download the free opti-swab study here.

The self-centering screw cap securely holds the swab in place, reducing the chance of contamination or leakage during transit.

In addition to its intuitive design, the Opti-Swab® system is backed by extensive quality control testing. 

Puritan also offers a range of swab configurations to support different collection sites, from nasopharyngeal and pediatric to wound and vaginal specimens. 

This flexibility allows clinics to standardize their transport solutions without sacrificing quality or performance. 

Need something custom? We’ve got you covered. 

Choosing Puritan means partnering with a trusted U.S.-based manufacturer committed to innovation, compliance, and support in clinical diagnostics.

Meet the Opti-Swab® Liquid Amies Lineup 

Puritan offers three configurations of the Opti-Swab® Liquid Amies Collection & Transport System to accommodate a variety of specimen collection sites. Each system features high-performance HydraFlock® swabs, 1 ml of Liquid Amies medium, and a leak-resistant, self-centering cap for safe and easy transport.

LA 106 – Standard Elongated Flock Swab

Ideal for: Nose, throat, vaginal, rectal, and wound specimens
Swab Type: Elongated HydraFlock® (3506-H with 80mm breakpoint)
Pack Size: 6 boxes of 50 individually wrapped systems (300/case)

Key Features:

• Molded breakpoint for safe and efficient sample transfer
• Soft swab tip for improved patient comfort
• Compatible with Copan’s WASP automation (validated in a 2014 study)
• Ready-to-use kit with an 18-month shelf life
• For in vitro diagnostic use

LA-117 - Opti-Swab 1ml Liquid Amies Transport Medium w/ 6"Ultrafine Flock Swab

• Designed for small or narrow anatomical spaces
• Soft, flexible shaft to minimize patient discomfort
  Compatible with gram stains, rapid tests, molecular platforms (with validation)
• Premium plastic components for product stability
• For in vitro diagnostic useIdeal for: Eye, ear, urogenital, and pediatric specimens
  
  

LA-116 - Mini-Tip Swab for Targeted Sites

Swab Type: Mini-tip HydraFlock® (3316-H)
Pack Size: 50 per box

Key Features:

• Compact swab tip for precision in small or sensitive areas
• Easy-to-use, leak-resistant vial and self-centering cap
• Suitable for culture, staining, and molecular applications (when validated)
• Made in the USA | 18-month shelf life | For in vitro diagnostic use

The Puritan Opti-Swab® Liquid Amies Collection and Transport System Performance Data

The Puritan Opti-Swab® Liquid Amies Collection and Transport System has been rigorously tested to ensure it maintains the viability of a wide range of bacteria during transport. 

Independent studies and in-house testing have demonstrated its ability to preserve both aerobic and anaerobic bacteria, as well as fastidious organisms, for up to 48 hours under recommended storage conditions.

Tests followed guidelines outlined in the Clinical and Laboratory Standards Institute (CLSI) M40-A2 document, which sets industry standards for evaluating microbiological transport systems. During these studies, various bacterial strains—including Pseudomonas aeruginosa, Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria gonorrhoeae—were inoculated into swabs and stored at both room temperature (20–25°C) and refrigerated conditions (2–8°C).

Results consistently met or exceeded CLSI M40-A2 acceptance criteria, demonstrating that the Opti-Swab® system effectively preserves bacterial viability during transit. See more here. 

These performance characteristics ensure that clinical laboratories can rely on the Puritan Opti-Swab® Liquid Amies Collection and Transport System to deliver accurate, reliable results, even when immediate processing is not possible.

Opti-Swab® vs. ESwab®: What’s the Difference?

Healthcare professionals seeking reliable transport systems for clinical specimens often compare options like Puritan’s Opti-Swab® and the ESwab®. Both systems are designed to maintain the viability of collected specimens during transport and are widely used in diagnostic microbiology.

While ESwab® is a commonly recognized name in the space, Opti-Swab® delivers an alternative that combines liquid-based Amies medium with versatile HydraFlock® swabs. Opti-Swab® supports a range of sample types and laboratory workflows and is manufactured by Puritan Medical Products in the United States.

For institutions evaluating swab-based collection systems, both Opti-Swab® and ESwab® represent established options. Choosing the right fit often comes down to compatibility with lab protocols, sample types, and institutional preferences.