Mold Testing vs. Mycotoxin Testing: What Can Each Test Tell You?

If you think mold may be affecting your health, one of the first questions is usually, “What test should I get?”

It’s a good question, but there’s no single answer. That’s because testing your building and testing your body answer very different questions. Knowing what each test can and can’t tell you helps you avoid two common mistakes: feeling falsely reassured by a “clean” result, or reading too much into a “positive” one.

Start With the Building

Before any lab test, the most important step is a careful look for moisture and water damage. Mold needs water to grow. A good inspector will look for leaks, stains, and hidden moisture, often using tools like moisture meters or thermal cameras. Testing works best as a follow-up to that search, not a replacement for it.

Air Samples

How it works: A pump pulls a set amount of air across a sticky slide. A lab then counts and identifies the mold spores.

What it can tell you: Which types of spores were floating in the air at that moment, often compared with an outdoor sample.

Limits: It’s a snapshot. Results change with weather, airflow, and activity in the room. Some molds, like Stachybotrys, are heavy and sticky and don’t release many spores into the air unless disturbed. A “normal” air test does not rule out a hidden problem.

Settling Plates

How it works: Small dishes of mold food are left open for a set time, then watched to see what grows.

What it can tell you: Whether living mold spores are landing in a space. This is a low-cost first look.

Limits: Only living spores grow, and only certain types grow well on the plates. Plates can’t detect dead mold fragments or mycotoxins.

Dust DNA Tests (ERMI and Similar)

How it works: A lab tests dust from your home for the DNA of specific molds.

What it can tell you: Because dust builds up over time, this can show which molds have been present in the building over months or years.

Limits: Finding mold DNA doesn’t tell you whether mold is growing right now, where the moisture source is, or how much exposure a person is getting. ERMI was first developed as a research tool, so results should be read alongside the building’s history and inspection findings.

Dust Mycotoxin Tests

How it works: A lab checks dust for specific mycotoxins, the chemicals some molds make.

What it can tell you: Whether certain mycotoxins are present in the home.

Limits: It can’t always tell where they came from or prove they’re causing anyone’s symptoms. A careful moisture inspection is still needed.

Testing the Person

Mold Allergy Tests

How it works: A blood or skin test checks whether your immune system has an allergic reaction to certain molds.

What it can tell you: Whether mold allergy may be behind symptoms like sneezing, itchy eyes, congestion, or asthma.

Limits: Allergy tests don’t measure mycotoxins. A negative allergy test means you probably aren’t allergic to those molds. It doesn’t mean a water-damaged building is safe for you.

Urine Mycotoxin Tests

How it works: A urine sample is checked for specific mycotoxins. Labs use different methods, called ELISA and LC-MS/MS, which detect toxins in different ways.

What it can tell you: Which mycotoxins your body was releasing at the time of the test.

Limits: A urine result can’t tell you:

• Where the exposure came from, since food can also contain mycotoxins
• When the exposure happened
• How much may be stored elsewhere in the body
• Whether a detected mycotoxin is causing your symptoms

Some practitioners give glutathione or recommend sauna sessions before the test to increase what the body releases. This approach is used in some practices but isn’t a standard method. Many conventional medical organizations don’t currently accept urine mycotoxin testing as a standard diagnostic test, while many environmental medicine practitioners find it useful as one piece of the puzzle.

No Single Test Gives the Whole Answer

Each test measures something different:

• A building test looks at the environment.
• An allergy test looks at allergic reactions.
• A urine test looks at what the body is releasing.

They are not interchangeable. The most helpful approach usually combines:

• A detailed history of your symptoms and exposures
• A thorough inspection for moisture and water damage
• The right environmental tests for your situation
• A medical evaluation that also considers other possible causes
• Careful interpretation of any lab results

The Bottom Line

Testing can be very helpful, but the most useful question isn’t “Is the test positive?” It’s this:

“What exactly did this test measure, and what can it really tell us?”

Asking that question protects you from false reassurance and from jumping to conclusions. Working with an experienced inspector and practitioner can help you choose the right tests and understand what the results mean for you.