Quick Facts
- Sample: Blood (serum, 2.0–5.0 mL)
- Fasting: Not required
- Turn-around: 2-5 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Pinpoint your trigger — Identify if rough pigweed pollen is causing your seasonal allergy symptoms
- Guide targeted treatment — Support personalized immunotherapy and avoidance strategies with precise IgE quantification
- Convenient testing — Order online without a doctor's referral; collect at a local lab
- Confidential care — Receive secure, private results to empower your allergy management decisions
Who Is This Test For?
- Individuals experiencing sneezing, runny nose, or itchy eyes during late summer and fall
- Those with seasonal asthma flare-ups coinciding with pigweed pollen exposure (August–October)
- People seeking to confirm allergen sensitization before starting immunotherapy
- Anyone wanting to monitor allergy progression or treatment effectiveness over time
- Health-conscious consumers looking for direct-access allergy testing without physician visits
How It Works – Just 3 Steps
- Order online - Purchase your test conveniently from home; no doctor's appointment needed
- Visit a lab near you - Bring your test order to a local collection site for a simple blood draw
- Get your results - Receive findings securely within 2-5 business days via your account.
FAQ
What does this test measure? It detects specific IgE antibodies to rough pigweed (Amaranthus retroflexus) pollen, confirming allergic sensitization (Thermo Fisher 2024).
Is this test accurate? Yes—ImmunoCAP FEIA technology demonstrates high sensitivity and correlates strongly with skin prick testing (AAAAI 2025).
Do I need to stop allergy medications before testing? No medication adjustments are necessary; IgE blood tests aren't affected by antihistamines.
Can I use this test for children? Yes, the test is suitable for all ages experiencing seasonal allergy symptoms.
What if my results are positive? Discuss findings with an allergist to develop a personalized treatment plan including avoidance and immunotherapy.
More Details
What is the purpose of this test?
This blood test measures the concentration of IgE antibodies specific to rough pigweed pollen in your serum. Rough pigweed (Amaranthus retroflexus) is a widespread allergenic weed that produces abundant pollen from August through October, contributing significantly to seasonal allergic rhinitis and asthma across many U.S. regions (Mayo Clinic 2024).
When you inhale pigweed pollen, your immune system may mistakenly identify it as harmful and produce IgE antibodies. These antibodies trigger histamine release, causing classic allergy symptoms. This test provides quantitative evidence of sensitization, helping you and your healthcare provider understand whether rough pigweed is a key allergen behind your symptoms.
Who would benefit from this test?
You may benefit from this test if you experience recurring seasonal symptoms during late summer and early fall when pigweed pollinates. Common indicators include persistent sneezing, nasal congestion, itchy or watery eyes, sinus pressure, coughing, or asthma exacerbations that worsen outdoors.
Individuals living near agricultural fields or pasturelands where pigweed thrives are particularly susceptible. This test is also valuable if you're considering allergen-specific immunotherapy and need laboratory confirmation of sensitization. Early and accurate diagnosis enables targeted interventions that reduce symptom severity and healthcare costs (AAAAI 2025).
When should I order a Pigweed, Rough (Common) Allergy IgE Blood Test?
Order this test when you notice allergy symptoms that coincide with pigweed's pollination season—typically August through October. Symptoms may include:
- Nasal congestion and runny nose
- Sneezing and postnasal drip
- Red, itchy, or watery eyes
- Sinus pressure causing facial discomfort
- Scratchy throat or coughing
- Wheezing or difficulty breathing
- Dark circles under the eyes
- Poor sleep quality due to nasal congestion
- Decreased sense of smell or taste
In rare, severe cases, anaphylaxis may occur, requiring immediate emergency care. Signs include rapid pulse, throat swelling, difficulty breathing, low blood pressure, or loss of consciousness. If you experience these symptoms, seek medical attention immediately.
How do I interpret the results?
Your results are reported quantitatively in kilounits per liter (kU/L) and categorized by class level. Here's how to understand your findings:
IgE Level: <0.10 kU/L
- Class: 0
- What it means: Negative — no detectable sensitization
IgE Level: 0.10–0.34 kU/L
- Class: I
- What it means: Borderline — uncertain clinical significance
IgE Level: 0.35–0.69 kU/L
- Class: II
- What it means: Positive — low level sensitization
IgE Level: 0.70–3.49 kU/L
- Class: III
- What it means: Positive — moderate sensitization
IgE Level: 3.50–17.49 kU/L
- Class: IV
- What it means: Positive — high sensitization
IgE Level: 17.50–49.99 kU/L
- Class: V
- What it means: Positive — very high sensitization
IgE Level: ≥50.00 kU/L
- Class: VI
- What it means: Positive — extremely high sensitization
IgE levels ≥0.35 kU/L indicate allergic sensitization, but clinical symptoms and exposure history must be considered for accurate diagnosis.
Values at or above 0.35 kU/L suggest you're sensitized to rough pigweed pollen. However, positive results don't always correlate perfectly with symptom severity—some individuals with low IgE levels experience significant reactions, while others with higher levels have milder symptoms. Always discuss your results with an allergist who can integrate laboratory findings with your clinical history.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No special preparation is required for this test. You don't need to fast or adjust your current medications, including antihistamines or allergy treatments. Unlike skin prick tests, blood-based IgE testing isn't affected by antihistamines, making it convenient and accessible.
Simply visit your chosen laboratory with your test order. A healthcare professional will collect 2.0–5.0 mL of blood in a serum separator tube. The sample is processed, refrigerated, and analyzed using ImmunoCAP Fluorescence Enzyme Immunoassay technology for precise quantification.
How often should I get tested?
Initial diagnosis
- Suggested interval: Once to confirm sensitization
Monitoring immunotherapy progress
- Suggested interval: Annually or as recommended by allergist
Evaluating new or changing symptoms
- Suggested interval: As symptoms warrant
Routine surveillance if asymptomatic
- Suggested interval: Generally unnecessary
Most individuals only need testing once for diagnostic confirmation. If you're undergoing allergen-specific immunotherapy, your allergist may recommend periodic retesting to assess treatment effectiveness. Repeat testing is also appropriate if your symptoms change significantly or if you relocate to an area with different pigweed exposure.
Why early detection matters
Identifying pigweed allergy early allows you to take proactive steps that improve quality of life. Accurate diagnosis enables targeted allergen avoidance—such as staying indoors during peak pollen hours, using HEPA filters, and monitoring pollen forecasts. It also guides appropriate medical interventions, including antihistamines, nasal corticosteroids, or allergen-specific immunotherapy.
Untreated seasonal allergies can progress to chronic sinusitis, worsen asthma control, and significantly impact sleep, productivity, and overall well-being. Early detection reduces symptom burden and healthcare utilization, supporting better long-term outcomes (PubMed Central 2020).
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