Rat E87 IgE Biomarker Testing
It measures IgE antibodies to rat allergen (E87) to assess sensitization; order through Vitals Vault and test at a Quest draw site.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
A Rat E87 IgE test is a targeted allergy blood test that looks for IgE antibodies your immune system may make in response to rat allergens.
It is most useful when your symptoms line up with exposure, such as working around laboratory rodents, living in a building with rodent infestation, or having a pet rat.
Your result does not diagnose an allergy by itself. It helps you and your clinician connect symptoms, exposure history, and other allergy testing into a practical plan.
Do I need a Rat E87 IgE test?
You may consider Rat E87 IgE testing if you get predictable symptoms after being around rats or rat-contaminated environments. Common patterns include sneezing, runny or stuffy nose, itchy or watery eyes, cough, wheeze, chest tightness, or flares of eczema that seem tied to a specific workplace, room, or task.
This test is especially relevant for occupational exposure, such as animal care staff, researchers, veterinary settings, pest control, or facilities where rodent allergens can be present in dust. It can also be helpful if you have asthma or chronic rhinitis and you suspect an indoor trigger but you are not sure which allergen is driving it.
You do not need this test for every allergy symptom. If your symptoms are clearly seasonal or you already have a confirmed trigger that explains your pattern, a broader inhalant allergy panel or a different targeted test may be more efficient.
Testing supports clinician-directed care rather than self-diagnosis, because treatment decisions depend on your symptoms, lung function (if asthma is involved), and the level and timing of exposure.
This is a laboratory-developed specific IgE blood test performed in a CLIA-certified lab; results should be interpreted with your clinical history and are not a standalone diagnosis.
Lab testing
Order Rat E87 IgE through Vitals Vault and complete your draw at a Quest location.
Schedule online, results typically within about a week
Clear reporting and optional clinician context
HSA/FSA eligible where applicable
Get this test with Vitals Vault
Vitals Vault lets you order Rat E87 IgE testing without needing to coordinate a separate lab requisition visit. After you place your order, you can complete your blood draw at a participating Quest location.
When your results are ready, you can use PocketMD to review what the number means in plain language and to plan smart follow-ups. That can include deciding whether you need additional allergen testing, how soon to retest after exposure changes, and what questions to bring to your clinician.
If your situation is more complex—such as persistent asthma symptoms, multiple indoor exposures, or unclear triggers—you can use Vitals Vault to add companion tests so your next step is based on data rather than guesswork.
- Order online and draw at a Quest location
- Clear, patient-friendly result context in PocketMD
- Easy re-testing to track changes after exposure reduction
Key benefits of Rat E87 IgE testing
- Helps confirm whether rat exposure is a plausible trigger for your respiratory or skin symptoms.
- Supports occupational health decisions when symptoms worsen at work and improve away from work.
- Distinguishes sensitization to rat from other common indoor allergens that can look similar.
- Guides practical exposure-reduction steps (cleaning, ventilation, PPE, pest control) by focusing on a specific trigger.
- Helps your clinician decide whether additional testing (broader inhalant panel or component testing) is worth doing.
- Provides a baseline to compare against future results after you change exposure or treatment.
- Pairs well with PocketMD so you can translate a lab number into next-step questions and a retest plan.
What is Rat E87 IgE?
Rat E87 IgE is a blood test that measures allergen-specific immunoglobulin E (IgE) antibodies directed against rat allergens. IgE is the antibody class involved in immediate-type allergic reactions, where symptoms can occur minutes to hours after exposure.
If you are sensitized, your immune system has learned to recognize rat proteins as “threats.” With exposure, that IgE can trigger mast cells and basophils to release histamine and other mediators, leading to symptoms such as nasal congestion, sneezing, itchy eyes, hives, or asthma flares.
A key point is that sensitization is not the same as clinical allergy. Some people have detectable specific IgE but minimal symptoms, while others have strong symptoms with modest IgE levels. Your exposure intensity, your airway sensitivity (especially if you have asthma), and other allergies all affect how the result shows up in real life.
What “E87” refers to
E87 is a lab coding convention used to identify the rat allergen extract used for testing. Different labs may label rat-specific IgE slightly differently, but the clinical intent is the same: to estimate whether you have IgE sensitization to rat allergens.
How this differs from total IgE
Total IgE measures the overall amount of IgE in your blood, regardless of what it targets. Rat E87 IgE measures IgE that targets rat allergens specifically, which is why it is more actionable for identifying a trigger.
Why rat allergens can be potent indoors
Rat allergens can be carried in dander, saliva, and urine proteins that settle into dust and fabrics. In workplaces with animals, allergens can become airborne during cage cleaning or handling, and symptoms may build over time with repeated exposure.
What do my Rat E87 IgE results mean?
Low (or undetectable) Rat E87 IgE
A low result usually means rat sensitization is unlikely, especially if you have not had recent or ongoing exposure. However, it does not completely rule out allergy-like symptoms from rat environments, because irritation, infections, or other allergens can mimic the same symptoms. If your exposure is intense and your story is very convincing, your clinician may still consider repeat testing later or a broader indoor allergen workup.
In-range Rat E87 IgE (lab-reported as negative or borderline)
Many labs report a threshold where results are considered negative, equivocal, or low-level positive. A borderline result can happen early in sensitization, with intermittent exposure, or when another allergen is the main driver of symptoms. The most helpful next step is to compare the result with your symptom timing and to look for alternative triggers (dust mite, cat, dog, molds, cockroach, or other rodents) if your pattern persists.
High Rat E87 IgE
A high result suggests you are sensitized to rat allergens and that exposure could plausibly contribute to symptoms. It does not predict reaction severity on its own, but higher values often increase the likelihood that symptoms are clinically relevant when exposure is present. If you have asthma, a high result is a reason to take exposure control seriously and to review an asthma action plan with your clinician.
Factors that influence Rat E87 IgE
Your level of exposure matters: frequent handling, cage cleaning, or living with ongoing infestation can increase the chance of sensitization. Timing can matter too—IgE may change over months, so results can lag behind exposure reduction or new exposure. Other allergies can complicate interpretation because cross-reactivity and multi-sensitization are common in people with allergic rhinitis or asthma. Medications like antihistamines do not typically suppress blood specific IgE results, but immune-modifying therapies and major health changes can affect your immune profile over time.
What’s included
- Rat (E87) Ige
Frequently Asked Questions
What does a Rat E87 IgE test measure?
It measures allergen-specific IgE antibodies in your blood that react to rat allergens (often from dander, saliva, or urine proteins). It is used to assess whether you are sensitized to rats as a potential trigger for allergy symptoms.
Do I need to fast before a Rat E87 IgE blood test?
Fasting is not usually required for specific IgE testing. If you are getting other labs at the same visit (like lipids or glucose), follow the fasting instructions for those tests.
Can antihistamines affect Rat E87 IgE results?
Antihistamines typically do not change blood specific IgE levels, so they usually do not affect the result. They can affect skin-prick testing, which is one reason a blood test may be chosen in some situations.
If my Rat E87 IgE is positive, does that mean I am definitely allergic to rats?
A positive result means sensitization, not a guaranteed clinical allergy. It becomes more meaningful when your symptoms reliably occur with rat exposure and improve when exposure is reduced. Your clinician may consider your history, exam, and sometimes additional testing to confirm clinical relevance.
What if my Rat E87 IgE is negative but I still react in a rat environment?
Symptoms can come from other indoor allergens (dust mite, mold, cockroach, cat/dog), irritants (ammonia, dust, cleaning chemicals), or asthma triggers unrelated to IgE. If the pattern is strong, consider broader inhalant testing and a review of exposure conditions and protective measures.
How soon should I retest after reducing exposure to rats?
Specific IgE can take months to change, so retesting is often considered after a sustained period of exposure reduction, commonly around 3–6 months, depending on your situation. Your clinician may also focus on symptom improvement and asthma control rather than the number alone.
Is this test useful for workplace (occupational) allergy concerns?
Yes. When symptoms are worse at work and improve on weekends or vacations, a targeted rat-specific IgE can support an occupational allergy evaluation. It can also help guide workplace controls and documentation discussions with occupational health.