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ISO 21326 Test

Test methods for determining the efficiency of products against house dust mite

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ISO 21326 : 2019 Determining the efficacy of treated textiles against dust mites

ISO 21326 specifies the test methods for evaluating the efficacy of chemically or physically treated textile products against house dust mites. These methods are as follows –

Textile products treated by chemicals against house dust mites –

Method A: Repelling method by using a petri dish

Products to be tested include carpet, bedding surface fabric, bed sheeting, bed covering, and blanket.

Method B: Repelling method by using glass tube (Methods A and B)

Products to be tested include wadding, wool or synthetic fiber, and feathers/down.

Method C: Proliferation method (Method A – petri dish method & Method B – glass tube)

Method A applies to carpet, bedding surface fabric, bed sheeting, bed covering, and blankets. Whereas, method B applies to wadding.

Method D: Penetration method

This method applies to the outer fabric of a futon, bed sheeting, and bed covering. However, this method can’t be employed for non-woven fabrics and fiber products with high stretch properties such as jersey fabrics.

ISO 21326 Test Requirements

House dust mite

House dust mites from the Pyroglyphidae family, commonly found on floors, carpets, and bedding, are utilized for testing.

Efficiency of repellency

The test determines the efficiency of repellency

Culture medium

Diet for breeding house dust mite

Mite medium

Combination of diet and live house dust mite

Rate of repellency

Determines the ratio of live mites in the treated material to those in the untreated material

Rate of suppression of house dust mite reproduction

Determines the ratio of the number of live mites in treated material to those of live mites in untreated material by the proliferation method

ISO 21326 Test Method

Repelling method by using Petri-dish

  • A small petri dish that contains the fabric sample and culture medium is placed in the center of the large petri dish.
  • Subsequently, in the large petri dish, the mite medium consisting of 10,000 mites is spread to facilitate mites migration to the small dish.
  • After the predetermined duration, the number of live mites that have entered into the small petri dish is counted.
  • The efficiency of repellency is calculated and compared to the number of live mites in a control test.

Repelling method by using glass tube, Method A and Method B

  • The fabric sample is placed in one end of the glass tube, with the sequence as follows – stuffing, culture medium, and the adhesive tape at the end. On the other opposite end of the test tube, a mite medium with 10,000 mites is placed to encourage mite migration.
  • After the predetermined duration, the number of live mites that can pass through the stuffing, the culture medium, and adhesive tape and intruding the mite medium are counted.
  • The efficiency of repellency is calculated by comparing the numbers of live mites with a control test.

The glass tube method A is employed for wadding samples, whereas the glass tube Method B is used for down and feather samples. In method B, a stainless steel mesh disc is used to position the test specimen within the glass tube.

Proliferation method by using Petri-dish Method A and using vial Method B

  • Between 50 to 80 live mites per 0.1 g of mite medium is introduced onto the textile sample in a petri dish or vial.
  • After the predetermined duration, the numbers of live mites on the petri dish or vial, the textile sample, and the mite medium are counted and their numbers are combined.
  • The suppression effect of house dust mite reproduction is determined by comparing the numbers of live mites in a control test.

The petri dish method A is for the carpet samples, etc. while vial method B is employed for wadding samples.

Penetration method

  • The textile sample is placed at the open end of the test tube and tightly enveloped in plastic wrap. At the bottom of the same glass tube, mite medium with 10, 000 mites is placed on a filter paper and tightly sealed.
  • After the predetermined duration, the number of mites on the fabric sample that pass through the plastic wrap is counted.
  • Efficiency for prevention is determined by comparing the number of house dust mites passed through the fabric sample and reference.

Importance of ISO 21326 Test

Anti-dust mite textiles are specially designed to mitigate the presence of house dust mites and allergic reactions associated with them. These textile materials act as physical barriers to dust mites and also effectively deter their infestations.

Testing is done to ensure the treated textile product’s effectiveness against dust mite strains, which subsequently helps in reducing allergen exposure.

ISO 21326 describes different test methods to evaluate the efficacy of textile products against dust mites and to ensure compliance with regulatory authorities.

At MIS, we are dedicated to performing entomology testing in support of the insecticide and pesticide industries for high-quality product development.

Our entomology testing labs are well-equipped with advanced technologies for rearing insect strains and conducting efficacy studies as per standard guidelines.

We have a team of experts who possess in-depth knowledge and experience in conducting
textile testing for dust mites and other pertinent bioassays as per intended application and efficacy claims of products.

Furthermore, tick-repellent tests also come within the scope of our testing capabilities.

For more information on the dust mite test, contact our team experts today.


ISO 21326 test is a standardized method used to assess the efficacy/resistance of textile materials that undergo physical or chemical treatment for controlling mite infestation.

ISO 21326 test applies to physically or chemically treated textile material that claims to deter house dust mite infestations. The textile products to be tested may include – carpets, bedding surface fabrics, bed sheetings, bed coverings (wadding), blankets, etc.

ISO 21326 test takes 6 – 8 weeks to complete.

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