How to Read/Interpret Mold Test Report Results

Mold tests can provide valuable insights that can make it easier to decide what the ideal plan of action is. That being said, figuring out how to read and understand mold test report results can be confusing for people who are not familiar the with the mold inspection process and with mold test reports. That is why we have have written this guide to make it easier for you to understand how to read and interpret mold test results.

What Information is Typically Provided in a Professional Mold Report?

While it is not possible to determine the amount of live or inactive mold in a property with a test, mold professionals can determine the type of mold, the mold spore concentration, a general idea of where the mold growth is located, and the amount of moisture in a property with testing.

Mold Report Terminology

In order to fully understand what a mold report is saying, you will need to understand what certain mold report terminology means.

Mold Counts – The baseline measurement of mold spores obtained from either an air or surface sample.

Mold Types – The species of mold that is present

Raw Count – This represents the amount of spores in a lab sample.

Spores/M3 or sp/m3 – This refers to the number of mold spores, that are present in one cubic meter of air.

% of the total – The proportion of a specific mold type in relation to all mold samples collected from a property. This metric allows for a better understanding of the prevalence and distribution of different types of mold in the affected area.

Sample Mold Test Report

sample mold test report

Types of Mold Tests

There are various different ways to test for mold within a property. Below are some of the most common approaches to mold testing.

Air Quality Testing for Mold

Using a spore trap, air sample can be collected and sent to a laboratory for analysis. This type of test allows for the identification of the mold species that’s present in a property and the detection of mold spore levels.

Mold Swab Sample Testing

To determine the type of mold present in a given area, one can swab the mold or a random surface in the property and sent it to a laboratory for analysis. That being said, it is important to note that the swabbing testing method does not provide information about the concentration of mold spores present.

Moisture Testing

Since mold needs moisture to grow using a moisture meter to determine the humidity in a particular property is a good way to also test for mold. Studies suggest that the ideal relative humidity for buildings is between 40%-60%. If the humidity is higher than that there is a chance that mold can grow. Additionally, thermal imaging cameras can be used to identify any active leaks or moisture in the property. This is likely going to be where the majority of mold is going to be.

Bulk Sampling

When there is visible mold growth, some of the mold contaminated building materials can be sampled and sent to a lab for analysis. This bulk sampling method can effectively identify the type of mold present and provide valuable insights for remediation efforts.

Commonly Found Mold Species

Some types of mold are more dangerous than others so it’s important to consider that in your assessment of them mold problems. Some types of mold only cause allergies, some can be pathogenic, and others a downright toxic. Here is some information about a few of the commonly found mold species in properties.


This is the most common type of mold found in properties. Usually these types of mold can crate allergic reactions, but is not super toxic.


This type of mold is often found in water damaged wood. It is more commonly found outdoors and can cause allergic reactions in people.


Typically, this mold thrives indoors and can be found in items such as carpets, fabrics, and under floorboards. Its appearance is characterized by a brown or occasionally olive-green hue with a texture that resembles suede. Inhaling Cladosporium spores can trigger an array of allergic responses, such as itchiness in the eyes, runny nose, sore throat, and skin infections. Additionally, it has been linked to respiratory problems like asthma, sinusitis, and lung infections.


This is a type of toxic mold that is widespread and comprises several different species. Inhaling Alternaria spores can exacerbate or cause conditions such as hay fever and asthma.


This is also referred to as black mold, is one of the most dangerous types of toxic mold and is commonly found indoors. The mycotoxins produced by this mold species can be fatal to animals and infants as they cause the lungs to bleed. The challenging aspect of black mold is that it often grows in hidden areas like behind walls and under ceilings and is resistant to standard air sampling techniques, making it difficult to detect.


This is comparable to Stachybotrys in terms of its harmful effects. However, Memnoniella can be distinguished from Stachybotrys by the way it releases spores. When viewed under a microscope, Memnoniella’s spores are released in chains, while Stachybotrys releases its spores in clumps.

What is Considered a High Mold Spore Count in an Air Quality Mold Spore Trap Test Report?

As long as there are no visible mold colonies forming and no water damage, any mold spore concentration below 200 sp/m3 in hones is normal and generally not cause for alarm. That being said, if these spores are from a toxic species like Stachybotrys, the acceptable level of mold is around 50 sp/m3.

Keep in mind that mold spores are floating around every property so they are not an issue in and of themselves. The only time mold spores become an issue is when there is a high concentration of them in a property or if there’s moisture present. This also is a good indication that there’s probably mold growing in that property also. That being said, each type of mold has its own acceptable mold spore level based on how toxic that type of mold is. Below are the acceptable mold spore levels organized by mold species.

What Level of Black Mold (Stachybotrys or Memnoniella) Spores is Considered Dangerous?

There are a few species of mold that people refer to as black mold. The mold common species of mold that people call black mold are Stachybotrys and Memnoniella. Since these types of mold are highly toxic, any amount of mold spores above 50 sp/m3 is considered dangerous and cause for action.

Penicillium/Aspergillus and Cladosporium Mold Acceptable Mold Spore Levels

Generally speaking, anything below 400 sp/m3 in a particular room of these mold species is considered acceptable for Penicillium/Aspergillus and Cladosporium. Since Penicillium/Aspergillus and Cladosporium are both much less toxic and dangerous than Stachybotrys (black mold), there can safely be higher levels of these types of mold spores in a property. It is also important to note that Penicillium/Aspergillus is the most common type of mold found in most buildings, so don’t panic too much if it is found in your property.

Does the EPA or CDC Have Acceptable Mold Level Standards?

Both the EPA and CDC say that they don’t currently have a set standard acceptable level for airborne concentrations of mold or mold spores.

What Level of Mold is Dangerous?

A tiny bit of mold is common in moist areas like in window sills or in the shower, but if you see any surface level mold on your walls, floors, or ceilings, this is generally a sign of significant mold growth and it is cause for alarm. You see, mold often grows behind walls where you can’t see it, so if you see surface level mold it’s likely just the tip of the ice berg. Chances are that there is a bunch of mold behind the wall and some sort of moisture problem too that needs to be addressed.

What to Do if You Have Dangerous Amounts of Mold Spores or Moisture in Your Property

If the mold tests reveal that you have dangerous amounts of mold spores or humidity in your property, it is crucial to take immediate action to mitigate the problem by calling an expert like us. We can develop a plan of action based off of the mold test results, and provide you with a free estimate of what it would cost to get rid of the mold in your property.


While mold testing cannot provide accurate information on how much mold is growing in your property, it can provide valuable insights that can help you determine: the type of mold, the mold spore concentration, an idea of where the mold growth is located, and the moisture in a property with testing.