IgE Blood Test (Total IgE): Normal Range by Age, High Levels and What They Mean
The essentials
Immunoglobulin E (IgE) is the antibody behind allergic reactions. A total IgE blood test measures all the IgE in your blood; a specific IgE test measures IgE against one allergen, such as dust mites or peanut. A high total IgE is common with allergies, asthma and eczema, but also with parasites and a few rare conditions. It never tells you what you are allergic to, and a normal value does not rule allergy out.
How do I read my IgE blood test result?
IgE is normally present in tiny amounts; most of it sits on mast cells and basophils, where contact with an allergen triggers the release of histamine[2]. Below is a fictitious US report with total and specific IgE, which are often ordered together.
| Test | Result | Reference range | Flag |
|---|---|---|---|
| Immunoglobulin E, Total | 780 IU/mL | 6-495 IU/mL | H |
| D. pteronyssinus (dust mite) IgE | 3.20 kUA/L | <0.35 kUA/L | H |
| Cat dander IgE | <0.10 kUA/L | <0.35 kUA/L | - |
- Total IgE: the overall amount of IgE, in IU/mL. One IU/mL is the same as one kU/L, so labs may print either unit[6].
- Reference range: the adult range of this lab (6 to 495 IU/mL is the Labcorp adult interval)[2]. Other labs use much lower upper limits, so always read your own report.
- Specific IgE lines: reported in kUA/L, the "A" meaning allergen-specific[6]. A value below 0.35 kU/L is generally considered normal[3]. Here the dust mite result shows sensitization; the cat result does not.
- Flag H: above the range. A high total IgE does not name the trigger, and sensitization means allergy only if it matches your symptoms[6].
An H next to IgE, or a long list of allergen lines? BloodSense explains every line of your report and helps you prepare questions for your doctor.
Get my IgE result explainedWhat is a total IgE blood test used for?
Labcorp lists the main use as evaluating immune status in possible atopic disease, meaning allergic conditions such as hay fever, allergic asthma and eczema[2]. It may be ordered for unexplained sneezing, itching, wheezing or rashes, allergic asthma, eczema or chronic hives[4]. It can also be ordered when a parasite infection or an immune system problem is suspected[5].
Total IgE has a clear role in allergic bronchopulmonary aspergillosis (ABPA), an allergic reaction to Aspergillus mold, mainly in people with asthma. The 2024 international guideline requires a total IgE of at least 500 IU/mL, together with proof of sensitization to the fungus, to make the diagnosis[8].
Total IgE vs specific IgE: what is the difference?
A total IgE test measures all IgE antibodies at once. A specific IgE test (the older name was RAST) measures IgE against a single allergen, with a separate result for each one tested[1]. Neither level predicts how severe a reaction will be[1].
For food allergy, the US expert panel sponsored by the National Institute of Allergy and Infectious Diseases recommends against using total IgE to make the diagnosis, and favors specific IgE or skin tests read with your history[7]. For allergens that can cause severe reactions, such as peanut, a lower cut-off of 0.10 kU/L may be used[3].
What is the normal range for total IgE by age?
IgE is very low at birth, rises through childhood up to about age 15, then slowly declines through adulthood[6]. That is why children have their own ranges. The table shows the Labcorp intervals for selected ages, in IU/mL (equal to kU/L)[2].
| Age | Male | Female | Source |
|---|---|---|---|
| 1 to 5 months | 1-30 | 0-16 | Labcorp[2] |
| 1 year | 3-200 | 2-100 | Labcorp[2] |
| 2 to 3 years | 6-366 | 4-227 | Labcorp[2] |
| 4 to 6 years | 14-710 | 6-455 | Labcorp[2] |
| 10 years | 22-1055 | 12-708 | Labcorp[2] |
| 17 years and older | 6-495 | 6-495 | Labcorp[2] |
Adult ranges differ widely between labs:
| Adult range | Source |
|---|---|
| 6-495 IU/mL | Labcorp (United States)[2] |
| 1.5-150 kU/L | Cleveland Clinic (United States)[3] |
| 0-75 kU/L | South Tees Hospitals NHS laboratory (United Kingdom)[5] |
200 IU/mL can be normal on one report and high on another: your laboratory's range prevails[4].
What causes high IgE levels?
- Common Allergic (atopic) conditions: hay fever, allergic asthma and food allergies[3]. About half of people with allergic rhinitis or asthma have a raised total IgE[2].
- Common Atopic dermatitis (eczema). Total IgE is often high, and the level tends to follow the severity of the eczema[2].
- Possible Smoking, which raises IgE in a proportion of smokers[1][6].
- Possible Parasitic worm infections, which can push IgE very high[5][6]. Your doctor may add a stool ova and parasites test and look at your eosinophil count.
- Possible Allergic bronchopulmonary aspergillosis in people with asthma, the only condition where IgE level is closely linked to disease activity[6][8].
- Rare Some autoimmune and inflammatory diseases, such as eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome) and bullous pemphigoid[5].
- Rare Hyper-IgE syndrome, an inherited immune disorder affecting fewer than 1 in a million people, mostly caused by changes in the STAT3 gene. It combines eczema, skin abscesses and repeated pneumonia[9]. Other inherited immune disorders, such as Wiskott-Aldrich syndrome, can too[6].
- Rare IgE myeloma, an extremely rare form of multiple myeloma[2][6].
Can you have allergies with a normal IgE level?
Yes. Many people with allergies and clearly raised specific IgE have a normal total IgE[2]. The World Allergy Organization states that total IgE is not a reliable marker of allergy and that low or normal values do not exclude an IgE-mediated disease[6]. A high total IgE with no positive specific IgE may have a non-allergic cause[6]. A very low total IgE makes allergy less likely[5]. A low IgE on its own is rarely a concern; if other antibodies are low too, your doctor may look at IgG blood test results, IgA levels and IgM levels.
Do I need to fast or stop antihistamines before an IgE test?
No fasting is needed for a total IgE test[4]. Some providers may ask you to stop certain medicines, such as antihistamines, so tell them everything you take and do not stop any medicine on your own[1]. Before the draw, check this list:
- Ask whether your provider wants you to pause antihistamines or other medicines.
- Bring your medicine list.
- Note your symptoms and likely triggers.
- Mention recent travel or possible exposure to parasites.
- Ask which allergens are on any specific IgE panel.
Practical tips are in our guide to what to expect at a blood draw.
When should I see a doctor about my IgE result?
When to see a doctor
- Emergency: call 911 for signs of a severe allergic reaction: trouble breathing, swelling of the lips, tongue or throat, wheezing, faintness or widespread hives after a food, sting or medicine.
- Within 24 to 48 hours if your asthma is getting worse despite treatment, if you have hives or swelling that keep coming back, or if you have repeated skin abscesses or lung infections with a very high IgE.
- At your next appointment if you feel well and your total IgE is mildly high, or if your specific IgE results show sensitizations you do not react to in daily life.
Questions to ask your doctor
- Is my total IgE high for my age, according to this lab's range?
- Do I need specific IgE tests or skin tests to find my triggers?
- Could a parasite infection explain my result, given my travel history?
- Should my eosinophil count be checked as well?
- Do my asthma symptoms call for an Aspergillus test?
Frequently asked questions
Can an IgE test tell me what I am allergic to?
Total IgE cannot. Only specific IgE tests, each aimed at one allergen, can point to a trigger, and even then the result must match your symptoms[1][6].
Is a positive specific IgE the same as an allergy?
No. It shows sensitization. False positives can also occur[1][6].
Is a blood allergy test as good as a skin prick test?
Both detect sensitization. Skin prick testing remains the first-line test in most cases. Skin tests should not be done on skin with active dermatitis or severe dermographism, and a blood test can help then[6].
Related tests
- IgG blood testThe most abundant antibody and what high or low levels mean
- EosinophilsWhite blood cells that often rise with allergies and parasites
- BasophilsThe cells that carry IgE and release histamine
- TryptaseMeasured after a severe allergic reaction
- Complete blood countWhere the eosinophil count appears on your report
- Gamma globulinsThe protein fraction that contains antibodies
- MedlinePlus. Allergy Blood Test. US National Library of Medicine. medlineplus.gov (accessed October 28, 2026)
- Labcorp. Immunoglobulin E, Total (test 002170). labcorp.com (accessed October 28, 2026)
- Cleveland Clinic. Immunoglobulin E (IgE): Function, Tests & Disorders. Updated June 12, 2025. my.clevelandclinic.org (accessed October 28, 2026)
- Testing.com. Total IgE Test. testing.com (accessed October 28, 2026)
- South Tees Hospitals NHS Foundation Trust, Pathology. IgE (Total) Allergy Test. southtees.nhs.uk (accessed October 28, 2026)
- Ansotegui IJ, Melioli G, Canonica GW, et al. IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper. World Allergy Organ J. 2020;13(2):100080. doi:10.1016/j.waojou.2019.100080 (accessed October 28, 2026)
- NIAID-Sponsored Expert Panel; Boyce JA, Assa'ad A, Burks AW, et al. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. J Allergy Clin Immunol. 2010;126(6 Suppl):S1-S58. doi:10.1016/j.jaci.2010.10.007 (accessed October 28, 2026)
- Agarwal R, Sehgal IS, Muthu V, et al. Revised ISHAM-ABPA working group clinical practice guidelines for diagnosing, classifying and treating allergic bronchopulmonary aspergillosis/mycoses. Eur Respir J. 2024;63(4):2400061. doi:10.1183/13993003.00061-2024 (accessed October 28, 2026)
- MedlinePlus Genetics. Autosomal dominant hyper-IgE syndrome. US National Library of Medicine. medlineplus.gov (accessed October 28, 2026)
This page is general information. It does not replace the advice of a doctor, who interprets your results with your symptoms, history and examination.
