What lab work should be ordered for suspected mold exposure?

Laboratory Testing for Mold Exposure

There is currently no validated laboratory test to assess human exposure to toxigenic mold, and routine lab work is not recommended for suspected mold exposure. 1

Key Evidence Against Routine Laboratory Testing

The American Academy of Pediatrics explicitly states that:

• No validated method exists to test humans for toxigenic mold exposure 1
• No standardized serologic tests can reliably assess exposures to mold and other agents associated with damp indoor environments 1
• Assays to detect mycotoxins and microbial volatile organic compounds in blood have been developed for research purposes but have not been standardized for clinical use, and it is unclear what levels are associated with health effects 2

When Laboratory Testing May Be Appropriate

For Allergic Manifestations (IgE-Mediated Disease)

If the patient has evidence of atopy or allergic symptoms (rhinitis, asthma exacerbation, allergic rhinitis), targeted allergy diagnostics are indicated 3, 4:

• Skin prick testing for mold allergens 3, 4
• Serum mold-specific IgE antibodies (e.g., Aspergillus, Penicillium, Alternaria, Cladosporium) 3, 4
• Supplemented by provocation testing when indicated 3, 4

Research shows that only 3-10% of the European population demonstrates mold sensitization, and elevated anti-mold IgE is found in approximately 11% of symptomatic exposed individuals 5, 4. The sensitizing potential of molds is relatively low compared to other environmental allergens 4.

For Immunocompromised Patients (Invasive Fungal Infection)

If the patient has immune compromise (neutropenia, transplant recipients, high-dose corticosteroids, advanced AIDS, chronic granulomatous disease), immediate cessation of mold exposure has absolute priority 3:

• Radiological imaging (high-resolution CT chest) 2, 3
• Microbiological cultures from appropriate sites 3
• Serum galactomannan (GM) antigen testing for Aspergillus 2
• Serological testing for invasive aspergillosis 3
• Immunological evaluation of immune function 3

For Hypersensitivity Pneumonitis

If hypersensitivity pneumonitis is suspected clinically:

• High-resolution CT findings should be integrated with clinical findings, but not used in isolation 1
• Serum antigen-specific IgG or IgA testing should NOT be relied upon solely to confirm or rule out the diagnosis 1
• Antigen-specific inhalation challenge testing and lymphocyte proliferation testing are not recommended 1

What NOT to Order

Avoid these tests as they lack clinical validation 1, 3, 4:

• Blood or urine tests for mycotoxins or mold metabolites 3, 4
• Serum IgG antibodies to molds (while research shows 25-35% of symptomatic exposed individuals have elevated IgG, these remain relatively constant over time and do not correlate with symptom severity) 5
• Microbial volatile organic compound (MVOC) measurements in blood 3
• Environmental air sampling for mold (this is not part of medical evaluation) 1, 3

Clinical Approach Algorithm

Step 1: Detailed history focusing on:

• Visible mold growth, water damage, musty odors in home/workplace 2
• Timing of symptoms relative to exposure 4
• Immune status (transplant, chemotherapy, HIV, corticosteroids) 2, 3
• Atopic history (asthma, allergic rhinitis, eczema) 3, 4

Step 2: Physical examination for:

• Respiratory findings (wheezing, crackles) 6, 4
• Allergic signs (pale nasal mucosa, pharyngeal cobblestoning, rhinorrhea) 6
• Signs of infection in immunocompromised patients 3

Step 3: Risk-stratified testing:

• Atopic/allergic patients: Skin prick testing and/or mold-specific IgE 3, 4
• Immunocompromised patients: Imaging, cultures, galactomannan, immune function tests 2, 3
• Suspected hypersensitivity pneumonitis: High-resolution CT with clinical correlation 1
• All others: No laboratory testing indicated 1, 3

Critical Pitfalls to Avoid

• Do not order mycotoxin testing in blood or urine—these are not validated for clinical use 1, 3, 4
• Do not order environmental mold testing as part of medical evaluation—this should be performed by industrial hygienists if needed for remediation purposes 2, 1
• Do not rely solely on IgG antibodies to diagnose mold-related illness—they may only confirm exposure, not causation of symptoms 1, 5
• Testing the environment for specific molds is usually not necessary for visible mold growth less than 10 square feet 1