Cladosporium herbarum (m2) IgE Biomarker Testing
It measures IgE sensitization to Cladosporium mold to help explain allergy symptoms and guide next steps, with easy ordering and results via Vitals Vault/Quest.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
This test checks whether your immune system has made IgE antibodies to Cladosporium herbarum, a common outdoor mold. The lab name often shows up as “m2” (the allergen code) and “specific IgE.”
A positive result can support the idea that mold exposure is a trigger for symptoms like sneezing, itchy eyes, congestion, cough, or asthma flares. A negative result makes Cladosporium less likely, but it does not rule out other molds or non-allergic causes.
Because symptoms overlap with colds, irritants, and other allergies, the most useful way to use this test is alongside your history and, when needed, other allergy markers. Your result is a tool for clinician-directed care, not a standalone diagnosis.
Do I need a Cladosporium Herbarum M2 IgE test?
You may want this test if your symptoms reliably worsen in damp, leafy, or outdoor environments, or during seasons when mold counts rise. People often consider it when they have persistent nasal allergies (allergic rhinitis), recurrent sinus symptoms, chronic cough, or asthma that seems tied to weather changes, yard work, basements, or older buildings.
It can also be helpful if you have “allergy-like” symptoms but you are not sure what is driving them. A targeted specific IgE test can narrow the list of suspects so you can focus on practical exposure reduction and discuss treatment options with your clinician.
This test is less useful when symptoms are clearly explained by an infection, reflux, smoke/chemical irritation, or when you need a broad first-pass allergy screen rather than a single suspected trigger. If you are unsure, PocketMD can help you decide whether to order one allergen or a broader panel based on your pattern of symptoms and exposures.
If you are already on allergy treatment or considering immunotherapy (allergy shots), testing can provide objective evidence of sensitization that helps guide next steps, but your clinician will still interpret the result in the context of your symptoms and exam.
This is a laboratory measurement of allergen-specific IgE (often ImmunoCAP-style methodology) performed in a CLIA-certified lab; it supports clinical decision-making but does not diagnose allergy by itself.
Lab testing
Order labs to measure Cladosporium herbarum (m2) IgE
from $29.49 at Quest Diagnostics
About 1 week
Schedule online — results typically within a week
Clear next steps
Guidance included, with follow-up care available
HSA / FSA
Eligible for pre-tax health spending accounts
Get this test with Vitals Vault
Vitals Vault lets you order Cladosporium herbarum (m2) specific IgE testing without having to coordinate a separate lab requisition visit. You complete checkout, visit a local Quest draw site, and then review your results in your Vitals Vault dashboard.
If your result is positive, the next question is usually “Does this match my symptoms, and what else should I test?” PocketMD can walk you through common follow-ups, like checking other molds, dust mites, or a total IgE level, and help you plan a sensible retest timeline if you are tracking changes.
If your result is negative but you still feel “allergic,” Vitals Vault makes it easy to expand to companion tests so you can map triggers more completely instead of guessing. You stay in control of what you order, and you can bring the report to your clinician for shared decision-making.
- Order online and draw at a Quest location
- Clear, shareable lab reports for your clinician
- PocketMD guidance for next-step testing and retest timing
Key benefits of Cladosporium Herbarum M2 IgE testing
- Helps confirm whether Cladosporium mold is a plausible trigger for your nasal or asthma symptoms.
- Separates allergic sensitization from look-alike problems such as irritant exposure or viral congestion.
- Supports targeted exposure-reduction steps (outdoor mold precautions, humidity control) instead of broad, unfocused changes.
- Guides whether you should broaden testing to other molds or common co-triggers like dust mites.
- Provides objective documentation that can help your clinician tailor allergy medications or consider immunotherapy.
- Improves interpretation when paired with total IgE and symptom timing, especially in multi-allergen environments.
- Creates a baseline you can trend over time if your exposures change or you start a treatment plan.
What is Cladosporium Herbarum M2 IgE?
Cladosporium herbarum is a widespread environmental mold found outdoors on decaying vegetation and sometimes indoors in damp areas. The “M2” label is simply the lab’s allergen code for this specific mold.
The test measures allergen-specific immunoglobulin E (IgE) in your blood. IgE is the antibody class involved in immediate-type allergic reactions. If you have IgE that recognizes Cladosporium proteins, it suggests your immune system is sensitized to that allergen.
Sensitization is not the same thing as clinical allergy. A positive result means your immune system can react, but whether it actually causes your symptoms depends on exposure level, your respiratory health (such as asthma), and whether other allergens are also in play.
How this differs from “mold toxicity” testing
This is an allergy test, not a test for mycotoxins or “mold toxicity.” It does not measure mold in your home, and it does not prove that a building exposure is the cause of your symptoms. It tells you whether your immune system has IgE that can respond to this mold.
Why mold IgE can matter for asthma and rhinitis
In sensitized people, mold exposure can contribute to inflammation in the nose and airways. That can show up as congestion, post-nasal drip, cough, wheeze, or increased rescue inhaler use. Knowing which allergens you are sensitized to can help you and your clinician focus on the highest-yield triggers.
What do my Cladosporium Herbarum M2 IgE results mean?
Low (negative) Cladosporium herbarum specific IgE
A low or negative result means the lab did not detect meaningful IgE sensitization to Cladosporium herbarum. This makes Cladosporium a less likely driver of your symptoms, especially if the test was done when you were not severely immunosuppressed. However, you can still have allergy symptoms from other molds, pollens, dust mites, pets, or non-allergic triggers like irritants or reflux.
In-range (expected) result
For allergen-specific IgE, there is not a single “optimal” number the way there is for cholesterol. Many people will have an undetectable or very low value, and that is generally considered expected. If your value is low but your symptoms strongly track with mold exposure, your clinician may still consider broader testing or alternative explanations.
High (positive) Cladosporium herbarum specific IgE
A high or positive result suggests you are sensitized to Cladosporium herbarum. Higher values often correlate with a greater likelihood of clinical reactivity, but the number alone does not predict how severe your symptoms will be. The most meaningful interpretation is whether your symptoms flare with likely exposures (outdoor leaf litter, damp environments) and whether you also have asthma or chronic rhinitis.
Factors that influence Cladosporium herbarum IgE
Your result can be influenced by overall atopy (your tendency to make IgE), which is why total IgE and other allergen tests can add context. Cross-reactivity between different molds can also lead to multiple positives even if one exposure is dominant. Timing matters too: IgE reflects sensitization over time rather than a single day’s exposure, so it may not rise and fall quickly with short-term changes. Some medications can reduce symptoms without changing IgE, and severe immune suppression can sometimes blunt antibody responses.
What’s included
- CLADOSPORIUM HERBARUM (M2) IGE
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Frequently Asked Questions
What does a Cladosporium herbarum (m2) IgE test measure?
It measures the amount of IgE in your blood that specifically recognizes Cladosporium herbarum mold proteins. This indicates sensitization, which may or may not match your real-world symptoms.
Do I need to fast before an allergen-specific IgE blood test?
Fasting is usually not required for specific IgE testing. If you are combining it with other labs that do require fasting, follow the instructions for the full set of tests you ordered.
Is a positive mold IgE test proof that mold in my home is making me sick?
No. A positive result shows your immune system is sensitized to that mold, but it does not identify where the exposure occurred or prove causation. Your symptom pattern, environment, and sometimes additional evaluation are needed to connect the dots.
Can antihistamines affect my Cladosporium IgE blood test result?
Antihistamines can reduce symptoms, but they generally do not change allergen-specific IgE levels in a way that makes the blood test unreliable. Steroids and other immune-modulating therapies may affect symptoms and inflammation, but IgE often remains detectable if you are sensitized.
How is this different from skin prick testing for mold allergy?
Both aim to identify sensitization, but they measure it differently. Skin testing looks for an immediate reaction in the skin, while this blood test measures circulating specific IgE. Blood testing can be convenient when skin testing is not available or when you prefer a lab-based approach, and your clinician may choose one or use both depending on your situation.
What other tests are commonly ordered with Cladosporium herbarum IgE?
Common companions include total IgE, other mold-specific IgE tests, and testing for frequent co-triggers like dust mites or pet dander. If asthma is part of the picture, your clinician may also consider lung function testing and an overall allergy/asthma management review.
When should I retest Cladosporium-specific IgE?
Retesting is most useful when something meaningful has changed, such as moving, major remediation, starting immunotherapy, or tracking a longer-term plan. Many people wait months rather than weeks because IgE reflects longer-term sensitization. PocketMD can help you choose a retest interval that matches your goal.