Can I test a patient for mold exposure or infection?

Can You Test for Mold in a Patient?

No validated laboratory test exists to assess human exposure to toxigenic mold, and routine testing for mold exposure is not recommended. 1

What Testing Should Be Avoided

The following tests have no clinical utility and should not be ordered:

• Mycotoxin testing in blood or urine – These assays are not standardized for clinical use, lack validation, and have no established correlation with health effects 1
• Serum IgG antibody testing to mold – This does not reliably indicate exposure or disease 1
• Environmental mold sampling as part of medical evaluation – This is not recommended by the American Academy of Pediatrics 1

When Laboratory Testing May Be Appropriate

Testing is only indicated when you suspect specific mold-related diseases, not for general "mold exposure":

For Immunocompromised Patients with Suspected Invasive Fungal Disease

Immediate removal from mold exposure takes absolute priority. 1 Then proceed with:

• Serum galactomannan antigen testing for Aspergillus 1
• Microbiological cultures from respiratory specimens (sputum, BAL) 2
• CT imaging (superior to plain radiography for invasive disease) 1
• Immunological evaluation of immune function 1
• Beta-D-glucan testing (though less specific, can be positive with multiple fungal infections) 2

For Immunocompetent Patients with Suspected Allergic Disease

• Skin prick testing with standardized mold extracts (Alternaria, Aspergillus, Cladosporium, Penicillium) to identify IgE-mediated sensitization in patients with atopic history and respiratory symptoms 1, 3
• Mold-specific serum IgE as an alternative to skin testing 1

For Suspected Hypersensitivity Pneumonitis

• High-resolution CT (HRCT) looking for centrilobular ground-glass nodules, mosaic attenuation, air-trapping, and three-density sign 1
• Serum antigen-specific IgG or IgA antibodies can support a putative mold exposure when exposure history is unclear, but should never be used alone to confirm or exclude the diagnosis 1

Critical caveat: Serum precipitins have poor diagnostic performance with sensitivity of only 39-76% and specificity of 61-82%. In one cohort, 60% of patients with positive mold precipitins reported no identifiable exposure, while 32% with negative precipitins had demonstrable exposure. 1

For Suspected Coccidioidomycosis (Endemic Areas Only)

Use multiple tests including:

• Direct visualization and culture of sputum, BAL, or biopsy material 2
• Urine and serum antigen testing (particularly in immunocompromised patients) 2
• Serology (serum antibody testing) 2

The Correct Clinical Approach

Instead of laboratory testing for "mold exposure," focus on:

1. Detailed exposure history – Ask specifically about visible mold growth, water damage, musty odors in home/workplace, timing of symptoms relative to exposure 1

2. Assess immune status – Immunosuppression, chemotherapy, transplant status, HIV/AIDS, chronic granulomatous disease 1

3. Identify specific mold-related syndromes:

   • Allergic rhinitis or asthma (IgE-mediated) 3, 4
   • Allergic bronchopulmonary aspergillosis (ABPA) 5, 4
   • Hypersensitivity pneumonitis 1, 4
   • Invasive fungal infection (immunocompromised only) 2, 4

4. Environmental remediation is the definitive treatment – Medical interventions cannot be effective until source elimination is complete 5

Common Pitfalls

• Do not order "mold panels" or "mycotoxin screens" – These are not evidence-based and may reinforce false beliefs about mold toxicity 1
• Do not rely solely on serum precipitins for hypersensitivity pneumonitis diagnosis given their poor sensitivity and specificity 1
• Do not test asymptomatic patients or those without specific risk factors for mold-related disease 1
• Remember that outdoor molds are more important allergens than indoor molds for most allergic individuals 6