The first step in assessment is to non-intrusively determine if mold is present by visually examining the premises; visible mold helps determine the level of remediation necessary. If mold is actively growing and visibly confirmed, sampling for its specific species is unnecessary.
Intrusive observation is sometimes needed to assess the mold level. This includes moving furniture, lifting (or removing) carpets, checking behind wallpaper or paneling, checking ventilation ductwork and exposing wall cavities. Detailed visual inspection and the recognition of moldy odors should be used to find problems. Efforts should focus on areas where there are signs of liquid moisture or water vapor (humidity), or where moisture problems are suspected.
The United States Environmental Protection Agency (EPA) does not generally recommend sampling unless an occupant of the space has symptoms. Sampling should be performed by a trained professional with specific experience in mold-sampling protocols, sampling methods and the interpretation of findings. It should be done only to make a particular determination, such as airborne spore concentration or identifying a particular species. Before sampling, a subsequent course of action should be determined.
In the U.S., sampling and analysis should follow the recommendations of the Occupational Safety and Health Administration (OSHA), National Institute for Occupational Safety and Health (NIOSH), the EPA and the American Industrial Hygiene Association (AIHA).
Types of samples include: