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Dec 5, 2021Print this page

How to Swab for the Flu | Comprehensive Flu Swab Test Guide

How to swab for the flu graphic

Following the low rates of influenza during the 2020 flu season, The Centers for Disease Control and Prevention (CDC) predicts that the 2021 season will be unpredictable and potentially severe. 

The COVID-19 pandemic has added another layer of complexity to the flu season ahead. COVID and the flu share a number of similar symptoms, which will make diagnostic testing particularly important this flu season. Clinicians can expect higher rates of testing to drive clinical decisions around whether to initiate antiviral treatment, perform other diagnostic testing, or implement infection prevention and control measures for influenza.

Getting a fast, accurate diagnosis will be critical in driving care decisions, but speed and accuracy will vary based upon the type of test performed and testing materials used.

How to swab for the flu

Learning the proper way to swab for the flu is crucial for ensuring accurate results. Use of high-quality products—including appropriate swabs, transport media and test kits—can help in accurately diagnosing influenza and reducing the potential spread of the virus.

Each of the flu tests listed above can be performed using nasopharynx (NP) swabs, throat swabs, NP or bronchial washes, nasal or endotracheal aspirate, or sputum testing. 

To perform an NP flu swab test, follow these steps:   

  1. Choose a swab with a flexible plastic handle and flock tip, such as Puritan’s PurFlock Ultra 6" Sterile Ultrafine Flock Swab w/Polystyrene Handle.
  2. Insert the swab into one nostril straight back (not upwards) and horizontally to the nasopharynx up to the measured distance on the swab handle.
  3. Rotate the swab up to 5 times and hold in place for 5 to 10 seconds to collect sample material.
  4. Remove the swab and insert into a vial containing 1 to 3 ml of viral transport media.
  5. Break the swab handle at the scored breakpoint line.
  6. Label the vial with appropriate patient information. 

Note: Sample collection should be followed according to manufacturer's product insert if using a swab provided in a diagnostic kit. 

Want to take these steps with you? Download our printable PDF here

What is a flu swab test?

A flu swab test is one of several options available for diagnosing influenza viruses in nasal, nasopharyngeal or throat specimens. Each of these tests requires that a healthcare provider rotate the inside of the patient’s nose, nasopharynx or the back of the individual’s throat with a swab, then store and transport the swab according to the test type procedure for analysis.

These tests may vary in their effectiveness due to a number of reasons, including the number of flu variants circulating and the type of testing methodology and materials used. To ensure the most accurate possible results, it is important to select your flu test swab with care.

Which is the best influenza swab?

Clinicians have several options in swabs when it comes to performing a flu swab test, but not every swab will generate the same level of accuracy. For maximum specimen access, swabs should be transported using appropriate transport media.

Swab options for flu testing include flocked swabs, cotton tipped swabs, rayon tipped swabs, and foam tipped swabs. 

1. Flocked swabs 

Flocked swabs may be made of a variety of fibers using a process of precisely placing short fibers to create a soft, velvet-like tip. Many physicians also find that patients report less discomfort following use of flocked swabs than with other swab types. However, flocked swabs’ greatest advantage comes at the microscopic level: the synthetic tip of a flocked swab is more abrasive than materials such as cotton, which means it collects and retains a greater amount of sample than other materials. For nasopharyngeal swab specimens, clinicians are best served with either a mini-tip or ultrafine flocked swab. 

2. Cotton tipped swabs

Traditional spun cotton tipped swabs have found use in a range of medical applications. They're absorbent, soft, inexpensive, safe and incredibly useful—but they are not recommended for specimen collection. This is because cotton does not easily release specimens from the swab tip. Cotton also has naturally occurring fatty acids that can interfere with microbiology processes. 

3. Rayon tipped swabs

Like the cotton swabs, rayon tipped swabs are made from spun fiber, but can be used for many applications where cotton would not be suitable, including specimen collection. These swabs are inexpensive, soft and absorbent options for a flu swab test.

4. Polyester tipped swabs

Polyester tipped swabs have excellent collection properties and offer superior specimen release. Polyester fibers have been tested and validated for use in specimen collection in microbiology, rapid diagnostic tests and PCR analysis. However, these swabs tend to be more costly than cotton or rayon.

5. Foam tipped swabs

Medical grade polyurethane foam is also a strong diagnostic tip material choice. Foam swabs come in a range of tip shapes, sizes and porosities, so the intended swab use will dictate which foam tipped swab will work best. 

The types of flu swab tests

There are several types of flu tests available, each, with varying degrees of speed and accuracy. Some tests may be better suited for children, elderly or sensitive patients, so it’s important to understand your options. Below are the most common flu tests.

1. Rapid influenza diagnostic tests (RIDTs)

The most commonly used flu tests, RIDTs work by detecting the viral antigens that stimulate a person’s immune response. These tests are easy to use and can provide results within approximately 15 minutes. 

2. RT-PCR, rapid molecular, and nucleic acid amplification assays

Reverse Transcription-Polymerase Chain Reaction (RT-PCR), rapid molecular tests, and nucleic acid amplification assays detect genetic material of the flu virus. RT-PCR tests may take a few days while rapid molecular and nucleic acid amplification tests can produce results in as little as 20 minutes. These tests are commonly used to identify the influenza virus in populations suffering from acute respiratory outbreaks, such as hospitals, elder-care facilities, long-term care facilities, and the like. 

3. Viral cell culture test 

Viral cell culture tests perform an extremely accurate and conclusive method for diagnosing influenza. Viral cell culture tests can determine the strain of virus and have become the most common test to help identify and track the spread of flu. However, results for these tests generally take 24 to 48 hours—or longer—as they must be sent to a lab. Some cultures may take up to 10 days. As a result, these tests are a better option for population health support, such as documenting the specific strains of influenza active in a given population or region or tracking the effectiveness of antiviral agents. Viral cell cultures can also be used to confirm or refute a rapid flu test result.

Stock up for flu swab tests

With flu season underway, it’s crucial for clinics, hospitals and diagnostic labs around the world to keep in stock the highest quality specimen-collection products available. After all, the best defense is a good offense. As health care professionals know, the best way to help prevent the spread of the flu is with accurate, fast diagnosis and immediate treatment.

For additional insight on performing a flu swab test, download our infographic

To learn more about how Puritan products can help you meet your flu testing needs, please contact us today. 

Learn How to Swab for the Flu Infographic CTA

Topics: Flu, Flocked Swabs, Diagnostics, Specimen Collection Procedure


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