If you think something in your home may be affecting your health, asking for a blood test can feel like the obvious next step.

If mold is the problem, shouldn’t it show up in my blood?

Not quite.

Certain blood tests can help doctors investigate an allergic sensitization to specific molds or diagnose particular mold-related medical conditions. But there isn’t one routine blood test that simply comes back and says:

“Yes, there’s hidden mold in your home and it’s causing your symptoms.”

The medical question is more complicated than that.

And at Mold Dog Network, Tina Craig is careful not to blur that line.

Mold Dog Network doesn’t interpret bloodwork or diagnose mold-related illness. That belongs with an appropriate healthcare professional.

Our job is to investigate the other side of the equation: is there hidden mold in the property, and where is it?

For a broader explanation of how health concerns and the home can intersect, read mold exposure symptoms and when your home could be part of the problem.

Can a Blood Test Detect Mold Exposure?

Sometimes, but probably not in the way you’re imagining.

A doctor can order certain blood tests when investigating a suspected mold allergy or a specific fungal-related condition.

One of the most common examples is a mold-specific IgE blood test.

What is a mold-specific IgE test?

IgE is a type of antibody involved in allergic reactions.

If your doctor suspects you may be allergic to a particular mold, a blood test can look for IgE antibodies directed against specific mold allergens.

A positive result can indicate that your immune system has become sensitized to that allergen.

But sensitization and illness aren’t automatically the same thing.

The 2023 AWMF clinical guideline on diagnosing health effects associated with indoor mold exposure makes this distinction clear: detecting mold-specific IgE shows sensitization, but a clinically relevant allergy has to be established alongside your symptoms, medical history and other appropriate testing.

In other words:

A positive mold IgE blood test doesn’t prove that mold in your house is making you sick.

It also can’t tell you:

• Where you encountered the mold
• When the sensitization developed
• How much mold you were exposed to
• Whether hidden mold is currently present in your home
• Which wall, floor or ceiling might contain growth

There are practical limitations to mold allergy testing, too.

The clinical guideline notes that 113 mold allergens from 30 mold species had been described in the WHO/IUIS allergen database, while only eight individual recombinant allergens from three mold species were available for molecular mold-allergy diagnostics at the point covered by the guideline.

That helps explain why mold testing isn’t as simple as running one blood panel that covers every possible indoor mold.

A negative specific-IgE result also doesn’t reliably exclude mold sensitization because available test extracts vary in composition and may not contain the relevant allergen.

Bloodwork can answer a narrow medical question. It can’t map the mold inside your home.

What Does a Positive Mold Blood Test Actually Mean?

This is where bloodwork is easy to misunderstand.

If your blood test detects specific IgE antibodies to a particular mold, it may mean that your immune system has become sensitized to that mold allergen.

If you also have symptoms that fit an allergic condition and a medical history that supports the connection, that result may help your doctor reach a diagnosis.

But a positive result doesn’t automatically mean your current house caused the problem.

Mold exists both indoors and outdoors. CDC notes that mold spores can enter buildings through windows, doors, vents and HVAC systems, as well as being carried inside on clothing, shoes and pets.

So a positive test doesn’t tell your doctor, “The mold is behind the bedroom wall.”

It also doesn’t automatically mean:

• You have “mold toxicity”
• Every symptom you’re experiencing was caused by mold
• Your home contains dangerous levels of mold
• You need a particular detox treatment
• You know where the relevant exposure occurred

The clinical guideline goes as far as saying that mold-specific IgE must be interpreted in conjunction with the patient’s history and clinical presentation.

That’s why Tina describes MDN’s role as helping connect two different investigations.

Your doctor investigates what’s happening medically.

The property investigation answers a different question.

If you want to understand the clinical side in more detail, read how doctors know if mold could be affecting your health.

If your bloodwork shows mold sensitization, let your healthcare provider determine what that means medically. If your home is still a concern, investigate the property on its own evidence.

What About IgG, Mycotoxin Tests and Other Mold Blood Tests?

Search online for mold testing and you’ll quickly encounter a long list of tests, panels and terminology.

Not all of them answer the same question and some aren’t recommended for routine investigation of indoor mold exposure at all.

Mold-specific IgG tests

IgG antibodies have legitimate uses in medicine.

For example, mold-specific IgG may be appropriate when a physician is investigating particular conditions such as hypersensitivity pneumonitis or allergic bronchopulmonary aspergillosis.

But that doesn’t make mold IgG a general test for whether your home is making you sick.

The 2023 AWMF guideline specifically states that mold-specific IgG has no diagnostic significance for immediate-type mold allergy and shouldn’t be used for that purpose.

That’s another reason to ask what a test is actually intended to diagnose before interpreting the result.

What about mycotoxin blood or urine testing?

This is an area where homeowners can encounter very strong claims online.

Mycotoxins are substances produced by certain molds under certain conditions. But testing for them in a person doesn’t provide the straightforward household-exposure answer that many people expect.

The American Academy of Allergy, Asthma & Immunology cautions that commercially marketed urine mycotoxin tests lack standardization, may produce false-positive or false-negative results, and don’t have established thresholds showing what constitutes a harmful level in the body.

The 2023 AWMF guideline is similarly clear: human biomonitoring of mycotoxins isn’t indicated for routine medical diagnosis of indoor mold exposure. It states that determining mycotoxins in blood, serum or urine currently has no significance for routine clinical diagnosis of indoor exposure.

That doesn’t mean your symptoms aren’t real.

It means the test itself needs to be scientifically appropriate for the question being asked.

If you’re confused by terms such as mold toxicity and mold poisoning, read what people mean when they describe mold poisoning.

Tests for fungal infections are different again

There are also specialized blood tests used when doctors suspect serious fungal infections.

For example, serum galactomannan can be used in the diagnosis of suspected invasive pulmonary aspergillosis.

That’s a very specific medical situation. It isn’t a screening test for whether an otherwise healthy homeowner has hidden household mold exposure. The AWMF guideline explicitly limits that test to the appropriate clinical indication.

Before spending money on a mold-related blood or urine test, ask three questions: What exactly does it measure? What condition is it validated to help diagnose? And how would the result change my medical care?

Can Normal Bloodwork Rule Out a Mold Problem in Your Home?

No.

This might be the most important takeaway in the article.

Normal bloodwork doesn’t mean your home is mold-free.

Your body and your building are two different things being investigated.

A doctor may be looking at allergy sensitization, respiratory conditions, immune responses or completely different causes of your symptoms.

None of those blood tests physically examines:

• The cavity behind your drywall
• The subfloor under your carpet
• The area surrounding a leaking window
• The wall below a roof leak
• Concealed areas around cabinetry
• Hidden moisture damage elsewhere in the structure

Even a negative mold-specific IgE test doesn’t reliably rule out sensitization, according to current clinical guidance.

And whether someone has a diagnosed allergy or not, mold may still exist inside a moisture-damaged building.

CDC notes that mold can grow wherever excessive moisture is present, including around leaking roofs, pipes and walls and in areas that have flooded.

That’s a building problem regardless of what appears on a blood panel.

Once mold or moisture damage is identified, the practical job is to understand where the problem is and address the source.

Tina describes the moment families reach that stage:

Don’t use normal bloodwork as a clearance test for your house. Medical testing evaluates you. An environmental investigation evaluates the building.

What If Your Doctor Suspects an Environmental Issue but You Don’t Know Where the Mold Is?

This is where the two sides of the investigation can come together without being confused.

Tina says Mold Dog Network receives referrals from healthcare professionals in different parts of the country.

That doesn’t mean a doctor referring someone for an environmental investigation has proven that mold caused the person’s symptoms.

It means there are situations where the medical provider, the homeowner or both want better information about the environment.

Your healthcare provider can investigate your symptoms, assess allergies and decide whether bloodwork or other tests are appropriate.

Mold Dog Network investigates the property.

A trained mold detection dog searches accessible areas for its target mold odor and alerts the handler to specific locations of concern.

That can be particularly useful when there’s been a roof leak, plumbing issue or other water intrusion but nobody knows which concealed building materials may have been affected.

Instead of trying to use bloodwork to tell you whether there’s mold behind a wall, you investigate the wall.

Instead of guessing which part of the property needs attention, the goal is to find the mold.

Learn more about a mold dog inspection to locate hidden mold on Mold Dog Network’s Mold Dog Inspections service page.

If your doctor is investigating your health but nobody can tell you where suspected mold may be hiding in your home, that’s the property question Mold Dog Network is designed to help answer.

So, Will Mold Exposure Show Up in Bloodwork?

Sometimes bloodwork can provide useful information about your response to certain molds.

Mold-specific IgE testing may identify sensitization to particular mold allergens. Other specialized blood tests have roles in diagnosing particular medical conditions.

But there’s no general blood test that proves hidden household mold caused your symptoms.

A blood test can’t tell you there’s mold beneath the floor.

It can’t identify the wall affected by an old roof leak.

And normal bloodwork can’t declare your home mold-free.

That’s why it helps to separate the two questions.

Let your healthcare provider investigate your health. Let an environmental investigation answer what’s happening in the building.

As Tina puts it:

If hidden mold is still the unanswered question, you don’t have to keep trying to solve it through medical tests.

You can investigate the property directly.

Schedule a mold dog inspection with Mold Dog Network and get clearer information about where hidden mold may be located in your home.