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Blood Test Tracker

Oak IgE

Measures IgE antibodies to white oak 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 t7, t007LOINC 6189-5

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What it is

Oak trees release pollen as winter turns to spring, and the season can start as early as mid-February in some places. This test measures IgE, a type of antibody, to an extract of white oak pollen (Quercus alba, ImmunoCAP t7). Oak belongs to the birch group of trees, whose pollen proteins are very similar. Results come in kilounits per liter (kU/L), and many labs also print a class from 0 to 6.

Why it matters

Oak pollen can cause hay fever symptoms such as sneezing, a runny nose and itchy eyes. A 2021 review says oak can make up as much as half of the pollen in the air in parts of the United States. It also says about 30% of people with allergies there are sensitized to oak. Having IgE to oak does not prove that oak is causing your symptoms. Oak and birch pollen are strongly cross-reactive, so a raised oak result often goes with a raised birch result. Your symptom pattern and the time of year matter too.

If it’s high

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

Common causes

  • Sensitization without symptoms
  • A true oak pollen allergy (hay fever in tree pollen season)
  • Cross-reacting IgE from birch, alder, hazel, beech or other trees in the birch group, since their pollen proteins are similar
  • 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 tree pollen season, which starts in late winter or spring in many places
  • Ask whether a birch test or a skin test would add information, since oak and birch pollen cross-react
  • If raw fruits, nuts or vegetables make your mouth itch, tell your clinician, since this pollen food syndrome is common with birch group pollen allergy

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, Allergy and Asthma Proceedings, Allergy, 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 oak pollen levels depend on climate and location
  • Other tree pollen allergies, especially birch, alder, hazel and beech, which share pollen proteins with oak
  • Which oak the test uses: this test uses white oak, and other oaks are separate tests
  • 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. Otherwise, talk with a clinician if you have a lasting stuffy nose, sneezing, itchy eyes or wheezing that seem tied to spring, even if this result is in the usual range.

Questions you could ask

  • Do raw fruits or nuts make my mouth itch, and does that matter for how we read my results?
  • Do my symptoms follow tree pollen season?
  • Would a birch test or a skin test add useful information?
  • Could my oak result be part of a wider tree pollen allergy?
  • My result is in the usual range but I still have symptoms in spring. What should we look at next?

Questions people ask

My birch and oak results are both raised. Is that two separate allergies?

Not always. Oak and birch pollen contain very similar proteins, so IgE made against one can also bind the other. Your clinician reads the two results together with your symptoms and when they happen.

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

Not by itself. The test shows that your immune system has made IgE to oak 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.

Which oak does this test use?

Most labs use white oak (Quercus alba), also called ImmunoCAP t7. Labcorp, for example, lists Virginia live oak as a separate test with a different code (t218).

Show the science and sources

For clinicians and researchers

Quantitative IgE to a white oak (Quercus alba) pollen extract (ImmunoCAP t7) by fluoroenzyme immunoassay. ARUP and Mayo both list LOINC 6189-5. 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). Oak belongs to the birch homologous group of trees (birch, alder, hazel, oak, hornbeam, chestnut and beech), a grouping based on extensive IgE cross-reactivity between homologs of the major birch allergen Bet v 1; the oak homolog is Que a 1 (Biedermann 2019, Bernstein 2021). A German expert group concluded that clinical trial data show birch pollen immunotherapy also works on pollen from alder, hazel and oak, and recommended focusing diagnosis and treatment mainly on birch as the representative allergen of the group, although some patients need further diagnostics (Kleine-Tebbe 2020). Many plant food allergens contain Bet v 1 homologs, and most patients with birch pollen allergy have secondary pollen food syndrome (Biedermann 2019). 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 6189-5 (primary). Specimen: serum.

Sources

  1. Allergen, Tree, Oak Tree (ARUP test 0055045), ARUP Laboratories
  2. Oak, IgE, Serum (test ID OAK), 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. Allergy to oak pollen in North America, Allergy and Asthma Proceedings (2021)
  7. Birch pollen allergy in Europe, Allergy (2019)
  8. Is allergy immunotherapy with birch sufficient to treat patients allergic to pollen of tree species of the birch homologous group?, Allergy (2020)

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

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