Test library
Sorghum Halepense Allergy Test
The Johnson Grass Allergy Test measures IgE antibodies to Sorghum halepense pollen, a common grass weed of warm regions. It helps evaluate seasonal allergy symptoms that follow exposure to this grass.
Order Johnson Grass Allergy Test
Order online and visit a local collection site, or choose an at-home kit where available. No referral and no insurance required.
Order Johnson Grass Allergy Test- Typical turnaround
- 1-3 business days
- Starting price
- From $49
- Results
- Confidential, online
Quick answer
The Johnson Grass Allergy Test checks for IgE antibodies against pollen from Sorghum halepense, a tall grass often found along roadsides and in fields. Its pollen is released in warm months and can contribute to seasonal allergic rhinitis. The test helps determine whether someone with summer or early fall symptoms has become sensitized to this particular grass.
What this test measures
Johnson grass is a perennial grass that grows in many warm and temperate regions. It pollinates in summer and can produce large amounts of lightweight pollen that travels in the air. Grass pollen is a common trigger for seasonal allergies.
The test measures specific IgE antibodies to Johnson grass pollen from a blood sample. A positive result indicates sensitization. Because grasses share some proteins, people may react to more than one grass, and a positive result is often assessed alongside other grass tests.
Testing may be ordered when symptoms such as sneezing, itchy eyes, or wheezing occur during grass pollen seasons, or when a clinician wants to identify which grasses are contributing. A qualified healthcare provider should interpret the result with the seasonal history.
- Johnson grass (Sorghum halepense) pollen-specific IgE antibodies
- Quantitative sIgE concentration reported in kU/L
- Allergen-specific IgE class on a graded scale
- Total serum IgE when included
- Blood eosinophil count when included
- Other grass pollen markers when a panel is included
Why people order this test
- Assess sensitization when warm-season symptoms occur
- Help identify which grass pollen may be triggering symptoms
- Add objective information to a seasonal allergy evaluation
- Compare with other grass sensitizations on a panel
- Check a specific grass when a broad panel is not needed
- Provide context for symptoms that appear near fields or roadsides
How to prepare
No fasting is required for this blood test. Follow the collection instructions provided by the laboratory, and note the months when symptoms appear so the pattern can be compared with the grass pollen season.
Understanding your results
Results are usually available within one to three business days. A detectable level indicates sensitization to Johnson grass pollen, though symptoms also depend on exposure and other sensitivities. A qualified healthcare provider should interpret the findings.
Sorghum Halepense Allergy Test by state
Alabama
Sorghum Halepense Allergy Test across Alabama.
Alaska
Sorghum Halepense Allergy Test across Alaska.
Arizona
Sorghum Halepense Allergy Test across Arizona.
Arkansas
Sorghum Halepense Allergy Test across Arkansas.
California
Sorghum Halepense Allergy Test across California.
Colorado
Sorghum Halepense Allergy Test across Colorado.
Connecticut
Sorghum Halepense Allergy Test across Connecticut.
Delaware
Sorghum Halepense Allergy Test across Delaware.
Florida
Sorghum Halepense Allergy Test across Florida.
Georgia
Sorghum Halepense Allergy Test across Georgia.
Hawaii
Sorghum Halepense Allergy Test across Hawaii.
Idaho
Sorghum Halepense Allergy Test across Idaho.
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Frequently Asked Questions
What is Johnson grass?
Johnson grass, or Sorghum halepense, is a tall perennial grass common in warm regions, along roadsides, and in agricultural fields.
When does Johnson grass pollinate?
It typically pollinates in summer and early fall, depending on the climate, and can release large amounts of airborne pollen.
Is Johnson grass pollen a common allergen?
Grass pollens in general are common allergens. Johnson grass is one of several grasses that may contribute to seasonal symptoms in warm regions.
Can I react to several grasses at once?
Yes. Grass pollens share proteins, so sensitization to more than one grass is common. Panels can show the overall pattern.
Does a positive test mean I have hay fever?
It shows sensitization to this grass. Whether it causes hay fever symptoms is determined by the clinical history and exposure.
Ready to get tested?
Order online and visit a collection site near you, or choose a mail-in kit. No referral and no insurance required.
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