As of yet, there are no EPA regulations or standards for indoor mold contaminants. Likewise, there are no Threshold Limit Values (TLVs) for mold concentrations against which a room or building can be measured to determine if or to what extent humans have been exposed to molds in that building. There are certain physiological and statistical tests that can help indicate if a person might have been exposed to mold. It is important to remember, however, that these tests are not commonly used; instead, they measure human exposure to molds in extreme situations. Humans are exposed to molds in the natural environment on a daily basis without any adverse effect on their bodies. If you can see or smell mold in your home or building, that means you have been exposed to the mold.

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A. Physiological Measurement Tools:

• 1. Measuring white blood cell counts: Though this test is not widely used when determining mold exposure, a person’s white blood cell (WBC) count can indicate that exposure has taken place. A higher than normal number of T-lymphocyte cells and natural killer cells—the body’s generalized defense system against foreign substances—can indicate higher than normal activity of the immune system, perhaps because of mold exposure.
  
  
• 2. Spirometric tests: “Spirometry” is a general term for a physiological test that measures lung function. These tests are much more commonly used in measuring human exposure to molds. There are many forms of spirometric tests, and they are often used in diagnosing other sorts of respiratory disorders (such as asthma). They may indicate human exposure to molds because inhaled fungus often results in impaired lung function or respiratory in humans. Here are some of the commonly used tests in measuring exposure to molds:
  
  
  • Forced Expiratory Volume in One Second (FEV1): In this test, the subject tries to exhale this highest volume of air possible in one second of a forced expiration. A person with normally functioning lungs can typically exhale 75% or more of their total lung capacity within one second.
    
  • Forced Vital Capacity (FVC): This basic test measures the total amount of air that a person can exhale from their lungs. It differs from the FEV1 test because there is no timed expiration; instead, the important factor is the maximum expiration potential of the subject.
    
  • Single Breath Carbon Monoxide Diffusing Capacity (DLCO): This test, somewhat more complicated than the previous ones, measures the body’s ability to exchange gases within the lungs. In this test, subjects inhale gas containing carbon monoxide; doctors can then monitor the levels of carbon monoxide in the bloodstream to study how well the lungs are allowing gases exchange across capillary membranes.
    
    
• 3. Skin prick tests: In these tests, similar to how doctors test for allergies, a person may be pricked with a mold allergen. If an allergic reaction occurs, or there is measurable production of certain human antibodies known to fight molds, then that could indicate human exposure to molds. For example, “IgE” is a common mold-induced antibody within the human body. These tests, however, are not performed nearly as often as the spirometric tests and can often produce misleading results. Because humans are exposed to molds in small amounts on a daily basis, this test can produce a false positive even the person has not been exposed to a dangerous amount of mold.
  

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B. Questionnaires:

Questionnaires designed to study mold exposure can help determine if statistically a person (or building) is at risk for mold exposure. The UK Sick Building Syndrome questionnaire inquires about whether a person has experienced symptoms common to those experienced by people with mold exposure, the severity of those symptoms, and possible exposures to mold-contaminated facilities. And example of this questionnaire can be found at http://www.lhc.org.uk/members/pubs/books/sbs/sba1.htm.

Who or What Types of People and Buildings are at Risk for Mold Exposure?

The keys to mold growth in a home are relative humidity and temperature. Molds grow bests in cool, damp areas of a building. Therefore, people most at risk for mold exposure are those that live in houses with moisture problems or that have experienced flood damage. Indoor humidity above 60% can promote mold growth. In particular, a leaky foundation or plumbing may be indications of a potential (or already existent) mold problem.

Sources:

AARC Clinical Practice Guideline (1999): Single Breath Carbon Monoxide Diffusing Capacity, 1999 Update. From Respiratory Care 1999;44(5):539-546. Available at: http://www.hsc.missouri.edu/~shrp/rtwww/rcweb/aarc/scmdccpg.html

Bishop, C: Molds. Available at: http://www.aehf.com/articles/molds.html

Hodgson, M. et al (1998): Building-Associated Pulmonary Disease from Exposure to Stachybotrys chartarum and Aspergillus versicolor. Journal of Occupational Medicine 1998; 40(3): 241-249.

Kilpelainen, M. et al (2001): Home dampness, current allergic diseases, and respiratory infections among young adults. Thorax 2001; 56(6): 462-467.

Page, E. and Trout, D. (1998): Mycotoxins and Building-Related Illness. Journal of Occupational Medicine 1998; 40(9): 761-763.

Priory Lodge Education Limited (1997): Spirometry Questions and Answers. Available at: http://www.priory.com/med/spiromet.htm

Respiratory Physiology Department – Prospectus. Available at: http://www.papworth-hospital.org.uk/what%20we%20do/thoracic/resp%20phys.htm

Sick Building Syndrome Questionnaire. Available at: http://www.papworth-hospital.org.uk/what%20we%20do/thoracic/resp%20phys.htm


U.S. EPA: A Brief Guide to Mold, Moisture, and Your Home, EPA 402-K-02-003, Washington. Available at: http://www.epa.gov/iaq/molds/moldguide.html