Quick Facts
- Sample: Serum (blood)
- Fasting: Not required
- Turn-around: 2-5 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Fast, accurate diagnosis - ImmunoCAP® technology delivers quantitative results in just 1-3 days (Thermo Fisher 2024)
- No physician referral needed - order online and visit any local lab for sample collection
- Personalized allergy insights - identifies Russian thistle sensitization to guide targeted avoidance and immunotherapy
- Supports treatment planning - helps allergists tailor medical therapy and monitor response over time
- Convenient and non-invasive - simple blood draw replaces uncomfortable skin prick testing
Who Is This Test For?
- Individuals experiencing seasonal allergy symptoms during Russian thistle pollen season (summer-fall in arid regions)
- People with unexplained rhinitis, asthma, or conjunctivitis in areas where Russian thistle grows
- Those seeking confirmation of suspected Russian thistle allergy before starting immunotherapy
- Anyone with known cross-reactive allergies to birch, olive, or kiwi fruit who suspects thistle sensitivity
- Patients monitoring treatment response to allergen-specific immunotherapy
How It Works – Just 3 Steps
- Order online - no doctor's referral required; select your test and complete checkout
- Visit a lab - bring your test requisition to any local or walk-in lab for a quick blood draw
- Get results - receive your confidential report within 2-5 business days via secure online portal
FAQ
What does this test measure? This test quantifies Immunoglobulin E (IgE) antibodies specific to Russian thistle (Salsola kali) pollen allergens in your blood.
Do I need to fast before the test? No fasting or medication restrictions are necessary before this blood test.
How accurate is this test? ImmunoCAP® FEIA technology offers high sensitivity and specificity, with strong correlation to clinical allergy symptoms (Mayo Clinic 2019).
Can I use this test if I'm taking antihistamines? Yes, unlike skin tests, blood IgE testing is not affected by antihistamines or other allergy medications.
Will this test diagnose all my allergies? This test only detects Russian thistle sensitivity; consider a comprehensive seasonal allergy panel for multiple allergens.
How soon after exposure can I test? IgE antibodies develop over time; testing is most accurate after repeated seasonal exposures to Russian thistle pollen.
More Details
What is the purpose of this test?
This test detects and measures IgE antibody levels specific to Russian thistle pollen, a major aeroallergen in arid and semi-arid regions. Russian thistle (Salsola kali) is a tumbleweed native to Europe and Asia that has naturalized across North America, Africa, Australia, and Asia (Corewell Health 2025). It thrives in salty soil and grows in wastelands, deserts, beaches, fields, and grasslands. The test identifies sensitization that may cause seasonal allergic rhinitis, asthma, and conjunctivitis, helping you and your healthcare provider confirm diagnosis and develop targeted treatment strategies.
Who would benefit from this test?
Anyone experiencing allergy symptoms during Russian thistle pollen season (typically late summer through fall) would benefit. This includes individuals with persistent nasal congestion, sneezing, itchy or watery eyes, coughing, or breathing difficulties when outdoors in affected regions. People planning allergen-specific immunotherapy should confirm Russian thistle sensitization before treatment. Those with known allergies to related species (birch, olive, kiwi) may also benefit, as Sal k 1—the most potent Russian thistle allergen—exhibits high cross-reactivity.
When should I order a Thistle, Russian Allergy IgE Blood Test?
Order this test if you experience allergy symptoms during Russian thistle pollen season or after exposure to tumbleweed-rich environments. Symptoms may appear within minutes to hours and vary from mild to severe. Common signs include:
- Nasal congestion, runny nose, or sneezing
- Red, itchy, or watery eyes
- Coughing, wheezing, or trouble breathing
- Sinus pressure causing facial pain
- Scratchy or sore throat
- Hives, itching, or skin swelling
- Dark circles under eyes
- Decreased sense of smell or taste
- Poor sleep quality due to congestion
In rare cases, severe allergic reactions (anaphylaxis) may occur, causing rapid pulse, throat swelling, difficulty breathing, low blood pressure, or loss of consciousness. Seek immediate medical attention if these symptoms develop.
How do I interpret the results?
Your results are reported as Russian thistle-specific IgE levels in kilounits per liter (kU/L). Higher values indicate stronger sensitization and greater likelihood of clinical allergy symptoms.
IgE Level: <0.10 kU/L
- What it means: Negative – No detectable sensitization
- Typical action: Russian thistle allergy unlikely; consider other allergens
IgE Level: 0.10–0.34 kU/L
- What it means: Borderline/Equivocal – Low sensitization
- Typical action: Correlate with symptoms; may retest or pursue additional testing
IgE Level: 0.35–0.69 kU/L
- What it means: Low Positive – Mild sensitization
- Typical action: Likely allergic; consider allergen avoidance and symptom management
IgE Level: 0.70–3.49 kU/L
- What it means: Moderate Positive – Moderate sensitization
- Typical action: Allergic; discuss avoidance strategies and medical therapy with provider
IgE Level: 3.50–17.49 kU/L
- What it means: High Positive – Strong sensitization
- Typical action: Significant allergy; consider immunotherapy and comprehensive management
IgE Level: ≥17.50 kU/L
- What it means: Very High Positive – Very strong sensitization
- Typical action: Severe allergy; aggressive avoidance and specialist consultation recommended
Always interpret results alongside your clinical history and symptoms—IgE sensitization doesn't always predict symptom severity (Thermo Fisher 2024).
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. You do not need to fast or stop taking medications, including antihistamines or other allergy treatments. Approximately 0.3-5 mL of blood will be collected in a serum separator tube. The sample should be refrigerated and shipped promptly to maintain stability. Continue your regular diet and medication schedule before testing.
How often should I get tested?
Testing frequency depends on your clinical situation and treatment goals.
Circumstance: Initial diagnosis of seasonal allergy symptoms
- Suggested interval: Once to confirm sensitization
Circumstance: Monitoring response to immunotherapy
- Suggested interval: Annually or as advised by allergist
Circumstance: New or worsening symptoms despite treatment
- Suggested interval: As needed to reassess sensitization
Circumstance: Confirmed allergy with stable symptoms
- Suggested interval: Retesting typically not necessary
Circumstance: Considering starting immunotherapy
- Suggested interval: Before treatment initiation
Why early detection matters
Early diagnosis of Russian thistle allergy improves symptom management, reduces healthcare costs, and prevents progression to chronic conditions like asthma (Mayo Clinic 2019). Identifying sensitization enables targeted allergen avoidance—staying indoors during high pollen counts, using HEPA filters, and limiting outdoor activities during peak season. It also guides appropriate medical therapy, including antihistamines, nasal corticosteroids, and leukotriene modifiers. For individuals with moderate to severe allergies, early detection allows timely initiation of allergen-specific immunotherapy, which can reduce symptom severity and medication dependence over time.
Related tests you may consider
Immunoglobulin E Blood Test, Total, IgE - Measures the total IgE antibody levels in the blood to assess the likelihood of experiencing allergic reactions.
Timothy Grass (Hay) Allergy IgE Blood Test - Measures the amount of allergen-specific IgE antibodies in the blood to detect an allergy to timothy grass or hay.
Kiwi Allergy IgE Blood Test- Measures the IgE antibody levels in the blood to detect an allergy to kiwi.
