ISO 18184 - Virucidal antimicrobial activity on textiles

What is ISO 18184 Testing?

The ISO 18184 test standard has been devised to examine the ability of textiles and other similar materials to eliminate viruses. The ISO 18184 testing method allows many virus types to be tested, including influenza and coronavirus strains. The standard contact time per ISO 18184 is 2 hours, but the protocol allows testing up to
24 hours.

How is it done?

Different types of viruses have varying sensitivity to the underlying material. This is overcome by including a control material while performing the test. When conducting the test, the control remains unaffected and is used as a benchmark against which antiviral activity of the treated material is measured.
The ISO 18184 testing method exposes the control/untreated and treated fabric to the virus for specified contact time as agreed between the lab and the customer. At the end of the contact time, the remaining virus is recovered using a neutralizing solution. The solution is serially diluted, and virus titration is calculated either
through a plaque assay or using TCID50.

The virucidal, antimicrobial activity of the treated textile is established using viral titer measurements through a plaque assay or the TCID50 method.

iso 18184 testing

The Plaque Assay

Plaque assays are conventionally used to count infectious particles. After the contact time, the remaining virus is extracted from the textile substrate using a neutralizing solution. The neutralizing solution is serially diluted and poured over the cell monolayer.

An agarose overlay is applied to restrict the movement of the virus. If the virus is present, then it will kill the cells and form a plaque.

The TCID50 method

The TCID50 (Median Tissue Culture Infectious Dose) assay is a popular technique to check the viral titer of a testing virus.  The assay works by adding serial dilutions of the virus sample to cells in a 96 well
plate. The cell type is specifically chosen to show morphological differences [cytopathic effect - CPE] upon viral infection or cell death. After incubation, the cells are examined for CPE or cell death. Each well is categorized as infected or not infected. The dilution, at which 50 % of the wells demonstrate morphological changes, is used to calculate the TCID50 of the virus sample. The Spearman-Karber method or the Reed-Muench method is used, and the viral titer is expressed as TCID50/ml.

Antiviral activity is calculated either as log reduction or percentage reduction on the test report.

Log Reduction Percentage Reduction Rating
Log 1 90% Fail
Log 2-3 99% to 99.9% Good
Log 3+ 99.9% Excellent

Why is this important?

The transmission of pathogens by textiles plays a significant role in the chain of infection. Textiles act as carriers of microbes that can remain viable for several days. These, in turn, contribute to the spread of infection. Antimicrobial, antiviral treatments kill the pathogens and prevent further spread of the disease. The ISO 18184 test is available for the following viruses: Influenza A (H1N1) (ATCC VR-1469), Feline Calcivirus (Strain: F-9)(ATCC VR-782), and Influenza A (H3N2) (ATCC VR-1679). Additional strains can be tested after validation.

Materials suitable for this test include woven, non-woven, knitted fabric, yarns, braids, etc.

The Applications

The ISO 18184 is used to determine the antiviral efficacy of an antimicrobial treatment applied on a textile substrate. The method is also used to test the wash durability of applied treatment so that customers will understand the number of washings for which the applied treatment will be useful in eliminating the virus.

Microbe Investigations

Founded in 2012, we are a spin-off company of the Swiss Federal Institute of Technology in Zürich. We offer specialized microbiological investigation services for the industry and aim at supporting the product development process of our partners in various sectors.

As an ISO 18184 testing lab, our team can help measure the antiviral activity of textile products. We test a wide range of textiles ranging from durable apparel to single-use textiles. These include face masks, bedding material, boxing gloves, leather bags, threads, medical drapes and gowns, jackets, jeans, Spunbond, Melt
blown, and spun lace. 

We are currently testing the following viruses: Influenza A (H1N1) (ATCC VR-1469), Influenza A (H3N2) (ATCC VR-1679), Beta Coronavirus (OC-43) (ATCC VR-1558), Human Coronavirus (229E) (ATCC VR-740), and testing SARS-CoV-2. For SARS-CoV-2, we can test the Delta, Wuhan, English, or the Brazilian variant. For additional viruses, please contact the MIS lab.

The ISO 18184 testing in our lab takes four weeks. The booking process is fast and straightforward. We will do the ISO 18184 testing at our lab and submit the report on the preferred date. 

For more information and to book a test, please reach out to us. We are happy to help!