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Mold Testing

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Mold Testing involves the collection of samples for one or both of the following purposes: 

(1) To assess the likelihood that mold growth has occurred in a suspect area.
(2) To assess the likelihood that indoor mold growth has negatively impacted the indoor air quality of a building. 

Mold testing answers the questions that the visual inspection cannot answer. Tests show what can't be seen. Has mold been growing indoors? Is it a health risk?

Mold Sample Types

There are three primary methods of testing for mold indoors; surface samples, air samples, and dust samples. A fourth method of detection is an instant result (no lab analysis required) swab test. These are less frequently utilized, because they offer no definitive data such as type of mold, yet still have their place in the Inspection and Testing process.

1. Surface Sampling

The purpose of surface sampling is to evaluate whether a suspected stain, discoloration, blemish, or other irregular appearance on a surface is mold. Just as the name implies, surface samples are used to identify what type of mold - if any - may be growing on the surface of construction materials, personal contents, etc. Surface samples are usually taken with a sterile cotton swab or tape lift and are only relevant to the exact area where the sample is taken. As such, surface samples are not to be relied upon for conducting risk assessment as it relates to airborne mold spore levels. 

Surface samples can be taken in a variety of ways. The three most common methods are:

  1. Bulk samples. A piece of the sampled area is physically removed and sent to the mold testing laboratory.

  2. Swab samples. Something akin to a cotton swab is rubbed across the area being sampled, often a measured area, and subsequently sent to the mold testing laboratory.

  3. Tape samples. A piece of clear tape is pressed against and removed from the area being sampled, presumably picking up and removing part of any mold that was present on the surface, and then sent to the mold testing laboratory for analysis. 

When Should Surface Samples Be Taken in a Mold Inspection?
As a rule, surface samples are unnecessary. Seeing visible mold growth indoors is usually enough to confirm that there is a mold problem. Mold should never be growing on any construction materials indoors or on anything stored indoors. Occasionally however, it can be difficult to distinguish the difference between mold and dirt with a visual inspection alone. For that reason, it is important to define your objective before deciding on whether or not to sample a surface for mold. 

The four most common questions people have for sampling surfaces are: 

  1. Is a certain stain or discoloration mold or dirt?
  2. What are the specific types of mold present on a surface?
  3. Is the mold on a surface viable or non-viable (alive or dead)?
  4. Is the mold on a surface the same mold that was found in an air sample taken from the same location? 

If your objective for sampling suspected mold on a surface is not one of these four reasons, surface sampling may be unnecessary. To discuss your specific situation and whether or not surface sampling will answer any questions you have, call a Certified Bluegrass Environmental Inspector today. 

2. Air Sampling

The purpose of air sampling is to evaluate the probability that an elevated or unusual mold condition exists indoors when such a determination cannot be made by visual observation alone.  

In a noninvasive inspection it is not always possible to visually determine if a "suspect condition", such as water damage or moisture is in fact a mold problem or not. Testing airborne mold spore levels near a suspect condition provides analytical data that can be used to either confirm or rule out hidden mold growth. 

This is achieved by collecting two air samples from outside a structure and at least one interior sample. The outside samples are analyzed by the laboratory and are utilized as a baseline/control sample against the interior sample. By documenting the naturally occurring mold species and levels of such molds outside a structure, it is then possible to compare such results against an interior sample and determine if mold levels are elevated above what could be naturally occurring with air transfer from outside to inside. 


3. Dust Samples

The purpose of Dust Sampling is to determine the species and quantity of mold spores that are present in dust. For example, we did testing in a building in Frankfort. Initial air samples indicated low concentrations of mold spores. We then disturbed the indoor air with an aerosol of sterile fluoroethane. The spore counts went up as high as 250,000 spores per cubic meter. Dust displacement allowed the spores in the dust to become redistributed into the indoor air offering a snapshot in time of what the air quality was within that structure during its normal operation.

Dust sampling can be performed by collecting debris from under appliances, above cabinetry, any area that is not regularly cleaned, allowing for an evaluation of contaminants settling over a long period of time. 

4. Instant Swab Test

An instant pass/fail test offers results in as little as 10 minutes. No lab work is required. Air sampling is the best indicator of a mold problem. However, the instant swab test is a less expensive alternative to determine if mold is present or not. It's a fast and easy way to check whether cleaning has been carried out to a satisfactory standard prior to encapsulating structural materials during the remediation/cleanup process. It is often utilized to determine if the black spots found in a building is actually  mold before performing a complete mold inspection. It is important to understand that the instant tests are testing by means of protein detection and do not show what type of mold or contamination levels. Many forms of the test may be purchased by individuals without having the credentials of a Certified Mold Inspector. Our service offers you third party documentation from a certified company as to the location of the testing and accuracy of results when such transparency may be required. 

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