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Blood Test Tracker

Mugwort IgE

Measures IgE antibodies to mugwort pollen in your blood. A detectable result means you are sensitized, which is not the same as an allergy.

AI-verified against cited sources. Awaiting expert reviewAlso called w6, w006LOINC 6183-8

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What it is

Mugwort is a weed in the daisy family, also called Artemisia vulgaris. In Europe, its pollen is one of the main causes of hay fever in late summer and autumn. This test measures IgE, a type of antibody, to an extract of mugwort pollen (ImmunoCAP w6). Results come in kilounits per liter (kU/L), and many labs also print a class from 0 to 6.

Why it matters

Mugwort pollen can cause hay fever symptoms such as sneezing, a runny nose and itchy eyes. One review reports that mugwort affects about 10 to 14% of people with pollen allergy in Europe. Having IgE to mugwort does not prove that mugwort is causing your symptoms, because some people have measurable IgE and no symptoms. Your symptom pattern and the time of year matter too. A minority of people with mugwort allergy also react to foods such as celery and some spices.

If it’s high

A level above your lab's range means your immune system has made IgE against mugwort pollen. This is called sensitization. In some people it goes along with hay fever in mugwort season. Others have no symptoms. The number does not say how strong your symptoms are.

Common causes

  • Sensitization without symptoms
  • A true mugwort pollen allergy (hay fever)
  • Cross-reacting IgE from other pollens, such as ragweed, which share some proteins with mugwort
  • IgE to a plant protein found in many pollens and foods, such as profilin, which can make several pollen results rise together
  • A very high total IgE (above about 2,500 kU/L), which can cause a false-positive reading

What can help

  • Talk with a clinician about whether your symptoms follow mugwort season, which is late summer and autumn in much of Europe
  • Ask whether a skin test or a more specific test, such as Art v 1 (the main mugwort allergen), would add information
  • If celery, spices or other plant foods make your mouth itch or cause other symptoms, tell your clinician

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 0–0.09 kU/L. Source: ARUP Laboratories, Mayo Clinic Laboratories, U.S. Food and Drug Administration, Journal of Allergy and Clinical Immunology, International Archives of Allergy and Immunology, Clinical & Experimental Allergy, Allergy, Asthma & Immunology Research, European Annals of Allergy and Clinical Immunology, MedlinePlus, National Library of Medicine.

ImmunoCAP IgE classes (ARUP labels and 0.10 cutoff; Mayo Clinic Laboratories class edges from 0.35 up)

  • Class 0: no significant level detectedbelow 0.1 kU/L
  • Class 0/1: clinical relevance undetermined0.1 to under 0.35 kU/L
  • Class 1: low0.35 to under 0.7 kU/L
  • Class 2: moderate0.7 to under 3.5 kU/L
  • Class 3: high3.5 to under 17.5 kU/L
  • Class 4: very high17.5 to under 50 kU/L
  • Class 5: very high50 to under 100 kU/L
  • Class 6: very high100 and above kU/L

What can affect your result

  • Season and where you live, since pollen levels change from place to place and year to year
  • Other pollen allergies, since mugwort shares proteins with ragweed and other pollens
  • Allergy to celery or spices, which some people with mugwort allergy also have
  • A very high total IgE (above about 2,500 kU/L) can cause false-positive results
  • The lab and test brand, because results from different systems are not directly comparable
  • Where a lab draws its cutoff (0.10 or 0.35 kU/L)
  • A very high total IgE (above about 2,500 kU/L) can cause false-positive results through nonspecific binding (Mayo Clinic Laboratories).
  • Antihistamines do not affect this blood test the way they affect skin-prick testing (NIAID 2010), but follow your clinician's instructions about any medicine before the test.
  • Different labs and test brands give different numbers for the same blood sample, so compare results from the same lab and system.

When to talk to a clinician

Get urgent medical help for severe trouble breathing, wheezing or chest tightness that does not ease, or swelling of the lips or throat. Call 911 or your local emergency number if celery, a spice or another food causes swelling of the lips or throat, trouble breathing, dizziness or fainting. Otherwise, talk with a clinician if you have a lasting stuffy nose, sneezing or itchy eyes that seem tied to late summer and autumn, even if this result is in the usual range.

Questions you could ask

  • Are there other pollens worth checking, such as ragweed or grasses?
  • Do my symptoms follow the mugwort season?
  • Would a skin test or a more specific test, such as Art v 1, add useful information?
  • Should we look at whether foods like celery or spices bother me?
  • My result is in the usual range but I still have symptoms in late summer and autumn. What should we look at next?

Questions people ask

Does a positive mugwort IgE mean I am allergic to mugwort?

Not by itself. The test shows that your immune system has made IgE to mugwort pollen, which is called sensitization. MedlinePlus notes that the amount of IgE does not predict how serious an allergy may be. Your clinician looks at the result with your symptoms and the time of year.

Why do some people with mugwort allergy also react to celery or spices?

Some proteins in mugwort pollen look like proteins in celery and certain spices, so IgE can bind to both. This is sometimes called the mugwort-celery-spice syndrome, and it happens in a minority of people with mugwort pollen allergy. Tell your clinician if foods make your mouth itch or cause other symptoms.

Is mugwort the same as ragweed?

No. Both are weeds in the daisy family, and their pollen shares some proteins, such as profilin. But their main allergens are unrelated proteins. Ask your clinician how to read your mugwort and ragweed results together.

Show the science and sources

For clinicians and researchers

Quantitative IgE to a mugwort pollen extract (Artemisia vulgaris, ImmunoCAP w6) by fluoroenzyme immunoassay. ARUP and Mayo both list LOINC 6183-8. The ImmunoCAP Specific IgE system reports up to 100 kUA/L with a limit of quantitation of 0.1 kUA/L, and its maker recommends a 0.35 kUA/L cutoff while telling each lab to set its own range (FDA review K173726). Art v 1, a defensin-like glycoprotein, is the major mugwort allergen. The lipid transfer protein Art v 3 is also a major allergen in Mediterranean patients: the three mugwort allergens tested each gave positive skin responses in 70 to 80% of 24 mugwort-allergic patients, and in some patients with IgE to both Art v 3 and the peach lipid transfer protein Pru p 3, Art v 3 appeared to be the primary sensitizer (Lombardero 2004). Among 148 Chinese patients with mugwort pollen allergy, 72% reported food allergy, which correlated with IgE to Art v 3 but not Art v 1 (Deng 2019). Art v 1 and the ragweed major allergen Amb a 1 are unrelated proteins, but both pollens carry profilin and calcium-binding proteins that cause cross-reactivity among pollen-sensitized patients (Wopfner 2005). The mugwort-celery-spice syndrome occurs in a minority of mugwort pollen-allergic patients, and in one index patient a 60 kDa allergen homologous to Api g 5 was proposed as the cross-reactive molecule (Borghesan 2013, a single-patient report). Cutoffs and predictive values do not transfer between assay brands (NIAID 2010). Mayo notes false positives can occur above about 2,500 kU/L total IgE.

LOINC 6183-8 (primary), 112149-0. Specimen: serum.

Sources

  1. Allergen, Weed, Mugwort (ARUP test 0055021), ARUP Laboratories
  2. Mugwort, IgE, Serum (test ID MUG), Mayo Clinic Laboratories
  3. 510(k) Decision Memorandum K173726: ImmunoCAP Specific IgE (ImmunoCAP Allergen f447, rAra h 6, Peanut), U.S. Food and Drug Administration (2018)
  4. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel, Journal of Allergy and Clinical Immunology (2010)
  5. Allergy Blood Test, MedlinePlus, National Library of Medicine
  6. The spectrum of allergens in ragweed and mugwort pollen, International Archives of Allergy and Immunology (2005)
  7. Prevalence of sensitization to Artemisia allergens Art v 1, Art v 3 and Art v 60 kDa. Cross-reactivity among Art v 3 and other relevant lipid-transfer protein allergens, Clinical & Experimental Allergy (2004)
  8. Mugwort Pollen-Related Food Allergy: Lipid Transfer Protein Sensitization and Correlation With the Severity of Allergic Reactions in a Chinese Population, Allergy, Asthma & Immunology Research (2019)
  9. Mugwort-fennel-allergy-syndrome associated with sensitization to an allergen homologous to Api g 5, European Annals of Allergy and Clinical Immunology (2013)

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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