At first, visual inspection is usually sufficient to assess whether you have a mold issue. If visual verification cannot be achieved, more advanced scientific tests such as swab samples, tape lifts or bulk samples may be required.
Mold testing answers these can provide valuable information about the types and numbers of spores present in your air by genus, as well as detect mycotoxins – neurotoxic chemicals associated with mold that are harmful.
Air Sampling
Air sampling is an increasingly popular mold inspection Charleston technique, providing a better picture of what conditions exist inside of homes.
This type of testing utilizes spore traps, small cassettes fitted with filters with narrow openings that impact surfaces to gather spores and fungal fragments from them. Once collected, these samples are sent off to laboratories where they are examined in terms of number and species of mold spores present.
Air sampling with viable samples involves taking samples in a similar fashion but including culture techniques in order to identify species-level mold. Although viable samples take longer for analysis, they can help identify specific kinds of mold such as Aspergillus fumigatus or Penicillium that can pose threats.
The laboratory also tests samples for mold inspector services related chemicals, such as mycotoxins (produced by Gram-negative bacteria that cause CIRS) and endotoxins. Results from such testing can provide an idea of whether levels are elevated which would indicate possible issues but cannot pinpoint an exact cause.
Surface Sampling
Surface samples of mold growth are taken using clear cellophane tape or sample kits containing cellulose swabs with liquid preservative, then pressed against visible mold growth before being sent off to be tested by laboratories. This method does not damage materials or structures and provides useful information about types of mold on surfaces while not providing insight into contamination levels.
Swab tests measure for certain enzymes produced by molds, such as N-acetylhexosaminidase (NAHA), to determine whether or not certain types of mold were present during and at the time and place where samples were taken. They do not provide definitive identification as they only show whether certain species existed at that point in time and space.
Surface samples may also be cultured for species identification and then examined through direct microscopy to identify mold species present; this method offers only partial information regarding types of spores present.
Bulk Sampling
Some dry or dormant molds found on building materials can be tested using swabs, tapes, or bulk samples for testing. These tests are less expensive and will quickly identify the genera (family name) of mold. Unfortunately, however, these tests will not indicate its size of growth or potential toxicity.
Environmental Relative Mouldiness Index (ERMI) air sampling requires home inspectors to take both indoor and outdoor samples in order to compare results and identify elevated mold levels in their home as well as identify any types present. This allows home inspectors to make an accurate determination regarding elevated levels of mold infestation, identify its sources and types.
Air sampling involves using a small portable pump to pull in an unknown volume of air through a disposable cassette that captures and counts spores for analysis, then compares them against an exterior control sample for comparison. A report will identify both live and dead spores as well as elevated counts of problematic species.
Direct Microscopy
Under this method, air is drawn into a small plastic or aluminum spore trap and sent to a laboratory for examination under microscope to identify mold spore species and count.
Testing at this level is the most costly and comprehensive way of knowing exactly which spores exist in the air at genus level, usually reserved for high exposures that require special handling or remediation efforts.
Conclusion
Experienced inspectors employ nonintrusive methods to detect problem areas. When possible, they opt for visual inspection over testing to solve visible growth. Testing can help justify cleaning expenses and confirm whether clean-up efforts met expectations, but should never serve as a replacement for visual inspection – the goal should always be finding and identifying issues safely and effectively so remediation efforts can proceed as intended.