InspectAPedia ^®

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. Here we discuss and provide photos of common indoor allergenic particles found in homes and in the work place. Also see CAT DANDER in buildings. Where toxic, pathogenic, or allergenic mold is a concern in buildings, see MOLD DETECTION & INSPECTION GUIDE and MOLD EXPERT, WHEN TO HIRE.

At ALLERGY TESTS for PEOPLE we discuss the types of allergy and allergy exposure tests used for humans, and at ALLERGY TEST ACCURACY we discuss the accuracy and limitations of those tests.

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.

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 Test For Dog, Cat, & Other Building Allergens

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)
• 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 We Screen Buildings for Animal Allergens?

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

There are chemical tests and assays for proteins (see ELISA and RAST below) 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.

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".

What Else Should We 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)
• 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 & GAS HEAT ODORS.
• 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.

Share this Article      

...

Technical Reviewers & References

• InspectAPedia.com^® - Daniel Friedman
• InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
• Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
• Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

ENVIRONMENTAL HAZARDS GUIDE
ALLERGEN TESTS for BUILDINGS
ALLERGENS in BUILDINGS, RECOGNIZING
ALLERGY TESTS for PEOPLE
ALLERGY TEST ACCURACY
ANIMAL ALLERGENS / PET DANDER
  PERSISTENCE of ALLERGENS
  CLEANING SUGGESTIONS
  DRUGS vs CLEANUP
  ALLERGEN DANDER STUDY
  PETS AS FAMILY MEMBERS
  REDUCING PET ALLERGENS
BOOKSTORE - ENVIRONMENTAL
BUYERS GUIDE - home inspections for mold
CAT DANDER
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
MOLD INFORMATION CENTER

• MedicineNet.com provides a detailed definition of ELISA at www.medterms.com/script/main/art.asp?articlekey=9099
• "IgG Food Allergy Testing by ELISA/EIA, What do they really tell us?" Sheryl B. Miller, MT (ASCP), PhD, Clinical Laboratory Director, Bastyr University Natural Health Clinic - ELISA testing accuracy: Here is an example of Miller's critique of ELISA http://www.betterhealthusa.com/public/282.cfm - Townsend Letter for Doctors and Patients
  The critique included in that article raises compelling questions about IgG testing assays, which prompts our interest in actually screening for the presence of high levels of particles that could carry allergens - dog dander or cat dander in the case at hand.
  http://www.tldp.com/issue/174/IgG%20Food%20Allergy.html contains similar criticism in another venue butinterestingly by the same author, Sheryl Miller. Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory. . Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory.
• Testing for the level of exposure to animal allergens is discussed at http://www.animalhealthchannel.com/animalallergy/diagnosis.shtml (lab animal exposure study is interesting because it involves a higher exposure level in some cases
• WebMD discusses allergy tests for humans at webmd.com/allergies/allergy-tests

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
• Environmental Health & Investigation Bibliography - our own technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
• ...

More Information on Building Diagnostic Inspections and Repairs

More Reading: specific to topics discussed in this document:
What indoor humidity should we maintain in order to avoid a mold problem?
Air Conditioning System Blower Fans & Filters Cascading for Optimum Indoor Air Quality The Use of Ozone Indoors for Control of Odors and Mold Removal in Buildings: A Summary of Hazards and False Claims.

• Allergen Tests in Buildings advice about how to test, what to look for, in evaluating the level of dog, cat, or other animal allergens in a building
• Animal Allergens: Dog, Cat, and Other Animal Dander - Cleanup & Prevention Information for Asthmatics and regarding Indoor Air Quality.
• Atlas of Mold Related Illness Symptoms & Complaints - incredibly long list
• Cat Dander: how to inspect and test a building for past or current presence of cats, cat hair, cat dander, and cat allergens
• Clinical Atlas of Mold Toxicity - An Online Description of Toxic, Pathogenic, Allergenic Fungi, Fungal Diseases
• Fiberglass Insulation Contains Mold© 2005 comments about a field study in process, & more about health hazards from fiberglass insulation - DJF
• Odors, Odor Detection, Smells, & Gases how to find and identify sources of noxious or toxic odors and gases
• Other environmental risks, Our much longer list: Asbestos, carbon monoxide, electromagnetic fields, etc.
• Pollen Allergens: identification,
• Products to Reduce Mold & Allergy Problems to reduce indoor mold or allergen levels: air cleaners, air purifiers, dust mite covers, vacuum cleaners, crawl space vents
• Recognizing Allergens: What various indoor allergens look like - identification photos to help identify pollen, dust mites, animal dander, toxic or allergenic mold - Common Mold and other Allergens, Irritants, Remedies & Advice
• Rodent control issues, including dander, fecal, and urine contamination of Buildings and Building insulation are discussed at our Mold Action Plan page.
• Sewage and Septic backup contamination in Buildings: inspection, testing, remediation, & references to expert sources
• Action Guide: What to do about mold, mildew, and other indoor allergens

InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

Building Inspection, Problem Diagnosis, Forensic Investigation & Testing, Repair Consulting

Contact Daniel Friedman for website content suggestions or for fee-paid consulting