Approaches to testing buildings for animal allergens:

This article describes how we perform a visual inspection and simple testing for the presence of high levels of animal allergens (dogs, cats, mice, birds) in buildings.

People often ask us how to test a building or home for cat, dog, or other animal allergens. This article explains and provide photos of common indoor allergenic particles found in homes and in the work place.

During building air quality inspections we often find evidence of cats, dogs, mice, birds, and other animals who have been frequently present in a home even though the human occupants didn't know it - either because the animal was the pet of a prior owner (chinchilla hair in photo below left at How to Test) or a nocturnal visitor to the food bins (mouse hair in photo below right at How to Test)).

When we find evidence of the past presence of animals in a building, additional cleaning might needed to reduce their remaining allergenic particles.

Allergen inspection & testing in buildings: how to find evidence of animal allergens indoors

Discussion here includes a review of evidence of Animals in Buildings: A List of Clues Indicating Past or Present Pets or Animals in buildings.

Our photos show skin cells (above) and dog and cat dander (below) stained pink with acid fuchsin.

How do You Test or Screen Buildings for Animal Allergens? IAQ: What Else Should You Check in Indoor Air & Dust Besides Animal Allergens?

Check With Your Doctor About Allergens and About Whether or Not Building Tests for Allergens or Mold are Recommended.

Animal dander in homes is a common source of respiratory irritants associated with asthma and allergies. Animal dander, hair, and other organic debris in homes can also result in a significant increase in the level of dust mites, mite fecals, and other allergenic insect parts and fragments.

These two lab photos of human skin cells, animal skin cells (dander), and other debris are typical of a home where pets have been resident. The left photo includes a feather barbule fragment and insect fecals. The right photo shows skin cells and animal dander.

How to Inspect & Test For Dog, Cat, & Other Building Allergens

Evidence of Animals in Buildings: A List of Clues Indicating Past or Present Pets or Animals in buildings

A List of Clues of Prior Animal Presence in a Building

While more sophisticated tests are available, simple adhesive tape sampling accomplishes this easily and is inexpensive.

During an inspection I also look for evidence of the pet history in the home - often there are left-over visual indicators even when pets are long gone or when recent owners didn't even have a pet. It may be important to look for evidence of animals other than pets, such as squirrels, mice, rats, insects, and birds, some of which can bear seriously harmful pathogens. Some telltales of prior animal or pet occupancy in a building include the following:

• Animal stains: grease, urine stains, marks of passage by doorways or sleeping areas. Animal stains may be seen on walls, trim, doors, carpets
• Remaining animal hair - even after cleaning, may show up in building dust or vacuum samples if collected with care
• Remaining cat litter can indicate that cats were present
• Pet doors
• Animal waste: outside around a home, inside the home, and in crawl spaces and attics (rodents, squirrels, raccoons, birds)
• Scratch marks doors, furniture, trim
• Stains on or damage to furniture (scratches, tears)
• Animal odors
• High levels of dust may indicate one or more dogs or other "indoor-outdoor" animals. I've found "dog dust" (a very find soil dust brought indoors by dogs, especially long-haired dogs) thick in building attics and even inside building wall cavities in buildings where multiple animals have been romping or living.

How do You Test or Screen Buildings for Animal Allergens?

Some Simple Building Tests for Animal Allergens - Screening for Allergenic Particles

The International Association of Allergology and Clinical Immunology (IAACI), also referred to as the World Allergy Organization, recommend collecting settled indoor dust to evaluate indoor building exposure to dust mite and other allergens. Dust mite allergens, a specific component of dust allergen surveys, are designated as Der P 1 and Der F1. 

High levels of dust mite allergens are associated with asthma or allergic sensitization and bronchial hyperactivity.  Although dog allergens, Can F 1 (Canine F1), exceed the low characterization, reaction to canine allergens is considered variable, ranging from 1-20 as significant. Cat allergens are actually more of a concern for many people than dog allergens.

See CAT DANDER for details.

There are chemical tests and assays for proteins in the dander of cats and dogs that check for the level of allergens in a building. But like any sophisticated chemical test or particle analytics which may appear to give very precise results (say a number to several decimal places), the results may be very inaccurate.

See ELISA and RAST

That is because in collecting building samples, almost everything depends on exactly where and how a sample is collected. To be accurate the sample must represent the actual conditions in the building and must accurately assay the probable level of exposure of occupants to the material being tested for.

Because of the risk of highly-inaccurate but costly "allergen tests", when I'm asked to inspect a property to assess the level of animal allergens present, I prefer to combine a thorough visual inspection with the information about the building history, prior occupants, any building-related complaints of the present occupants, along with the collection of carefully chosen building dust screening samples in which we look for high levels of animal dander or other diagnostic particles.

An "air test" to screen for animal allergens would be quite unreliable in addressing this question. Collect settled dust that represents building conditions and look for dominant particles and relative percentages of particles rather than "an airborne particle count".

OPINION-DF: We like to collect individual dust samples from representative building areas where we suspect a high allergen presence, and screening dust samples from rooms where building occupants spend the most time. That approach permits building diagnosis by identifying problem areas and their effect on other building areas.

OPINION-DF: An alternative to collecting settled dust from individual surfaces is to collect a composite dust sample by using an air-filter type cassette or a vacuum cassette that samples from multiple areas as a more general building screen, but if such a test comes back as "action needed" either we need to repeat the tests with more attention to individual areas, or the cleaning and action advice for the building will have to be very general.

What Else Should You Check in Indoor Air & Dust Besides Animal Allergens?

When screening a building for evidence of a high level of animal allergens, at the same time we look for the following:

• high levels of dust mite fecals
• high levels of insect fragments (cockroach, for example)
• the level of feather barbules and fragments
• the level of rodent presence (openings, gnaw marks, urine odors, droppings, odor, traps, mouse or rat animal dander) - also
  
  see FIBER & HAIR IDENTIFICATION
• the presence of materials commonly considered allergenic to some people: feather comforters, wool, lots of wall to wall carpets
• the general moisture level and leak history in the building (high moisture invites both mold contamination and higher levels of dust mites)
• the condition of the HVAC system air handler, duct work, filters, and filtration system

Check With Your Doctor About Allergens and About Whether or Not Building Tests for Allergens or Mold are Recommended

Of course since individual sensitivity to allergens varies, we suggest that anyone suffering from allergies and considering steps to further clean their home should also consult with their allergist and their general physician.

• Safety Warning: if indoor air quality complaints include respiratory distress, headaches, nausea, and similar symptoms, it is important to immediately rule out unsafe heating equipment, chimneys, flues, or carbon monoxide hazards.
  
  See CARBON MONOXIDE - CO.
• The types, accuracy, and variability of human tests for allergy sensitivity and allergy or mold exposure are discussed further
  
  at ALLERGY TESTS.
• The combination of allergy testing limitations and occupant complaints that may in some cases justify a building survey for physical particles or other evidence of significant levels of problem allergens, molds, or other conditions is discussed
  
  at ALLERGY TEST LIMITATIONS.
• See MOLD EXPERT, WHEN TO HIRE for advice on determining when it is appropriate and justified to order inspections and tests of a building for mold or allergens.
• See BIOLOGICAL POLLUTANTS for information about recognizing and removing these indoor contaminants.
• See ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY for our full list of environmental hazard identification and remedy related to buildings.

...

Continue reading at ALLERGY TESTS for PEOPLE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Allergen Articles

• ALLERGENS in BUILDINGS - home
  • ALLERGEN TESTS for BUILDINGS
  • ALLERGY & MOLD IAQ & CLEANING PRODUCTS
  • ALLERGY TESTS for PEOPLE
  • ALLERGY TEST ACCURACY
  • ANIMAL ALLERGENS / PET DANDER
    • CAT DANDER in BUILDINGS
    • PET STAINS & MARKS in BUILDINGS

Suggested citation for this web page

ALLERGEN TESTS for BUILDINGS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING ALLERGENS

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