Immunoglobulin E (IgE), Total
Total IgE is the overall amount of this allergy-related antibody in your blood. High levels are common with allergies, but the test can't show what you react to.
AI-verified against cited sources. Awaiting expert reviewAlso called IgE, tIgELOINC 19113-0
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What it is
IgE is an antibody that your immune system makes in small amounts. It plays a central part in allergic reactions. It sits on immune cells called mast cells and basophils, and when an allergen sticks to it, those cells release histamine and other chemicals. This test measures all of the IgE in your blood, whatever it reacts to. Levels are very low in babies, rise through childhood and the teen years, and settle in adulthood, so labs set ranges by age and sex.
Why it matters
A high total IgE often goes along with allergic conditions such as hay fever, allergic asthma and eczema. But it is a broad measure. It can't tell you what you are allergic to or how serious an allergy is, and many people with allergies have a normal total IgE. Clinicians usually read it together with your symptoms and, when needed, tests for specific allergens.
If it’s low
A low total IgE is uncommon, and it can't confirm a condition by itself. In studies of people tested for medical reasons, very low levels (under about 2.5 IU/mL) were linked to a higher chance of immune or autoimmune conditions. Those studies come from selected groups, so they can't predict risk for any one person. Your clinician can put a low result in context.
Common causes
- Young age: babies normally have very low IgE
- Not having an allergic tendency
- Less often, an underlying immune condition, which has been reported in specialist-clinic studies of people with low IgE
What can help
- Mention a low result to your clinician, especially if you have frequent or unusual infections
- Compare results over time using the same lab
If it’s high
A high level most often goes with allergic conditions such as eczema, asthma or hay fever. Infections with parasites and a few uncommon immune or lung conditions can also raise it. A high result on its own doesn't show which of these is behind it.
Common causes
- Allergic (atopic) conditions, such as hay fever, allergic asthma, eczema and food allergy
- Smoking
- Parasitic infections
- Allergic bronchopulmonary aspergillosis, a lung reaction to a mold
- Some uncommon inherited immune conditions, including hyper-IgE syndromes
- Graft-versus-host disease after a stem cell transplant
What can help
- Ask your clinician whether tests for specific allergens, or a visit with an allergy specialist, could help find triggers
- Keep a short diary of symptoms and of what you ate or were around before they started
- If you smoke, ask your clinician about support to quit
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.
The usual range depends on sex and age. Choose women or men to see the one that applies.
- 17+6–495 IU/mL
Sources: Labcorp, ARUP Laboratories
Children and teens 25 ranges
- Men, 1618–628 IU/mL
Source: Labcorp
- Women, 169–472 IU/mL
Source: Labcorp
- Men, 14–1520–798 IU/mL
Source: Labcorp
- Women, 14–159–681 IU/mL
Source: Labcorp
- Men, 1319–893 IU/mL
Source: Labcorp
- Women, 139–681 IU/mL
Source: Labcorp
- Men, 1216–810 IU/mL
Source: Labcorp
- Women, 1212–796 IU/mL
Source: Labcorp
- Men, 1122–1,055 IU/mL
Source: Labcorp
- Women, 1112–796 IU/mL
Source: Labcorp
- Men, 1022–1,055 IU/mL
Source: Labcorp
- Women, 1012–708 IU/mL
Source: Labcorp
- Men, 7–919–893 IU/mL
Source: Labcorp
- Women, 7–912–708 IU/mL
Source: Labcorp
- Men, 4–614–710 IU/mL
Source: Labcorp
- Women, 4–66–455 IU/mL
Source: Labcorp
- Men, 2–36–366 IU/mL
Source: Labcorp
- Women, 2–34–227 IU/mL
Source: Labcorp
- Men, 13–200 IU/mL
Source: Labcorp
- Women, 12–100 IU/mL
Source: Labcorp
- 0.583–02–82 IU/mL
Source: Labcorp
- Men, 0.5–-0.417000000000000042–52 IU/mL
Source: Labcorp
- Women, 0.5–-0.417000000000000041–24 IU/mL
Source: Labcorp
- Men, 0.083–-0.51–30 IU/mL
Source: Labcorp
- Women, 0.083–-0.50–16 IU/mL
Source: Labcorp
See Total IgE by age and sex, with the U.S. survey numbers where they exist.
What can affect your result
- Age: levels are lowest in babies, climb through childhood and the teen years, and settle in adulthood
- Sex: in many childhood age groups, boys have higher levels than girls
- Allergic conditions such as eczema, asthma and hay fever
- Parasitic infections
- Smoking
- Assay and lab: ranges differ between labs
- ARUP rejects hemolyzed, icteric or lipemic samples.
- Labs use different assay systems, units and age cutoffs, so compare results from the same lab.
When to talk to a clinician
A total IgE result is not an emergency by itself. Call 911 or your local emergency number right away for signs of a severe allergic reaction, such as trouble breathing, swelling of the tongue, lips or throat, dizziness or fainting, a fast heartbeat, or cold, clammy skin that looks pale, gray or bluish. Talk with a clinician if your result is far above your lab's range, especially with repeated infections or long-lasting skin or lung problems.
Questions you could ask
- Which lab range applies to me, given my age and sex?
- Could this fit with an allergic condition I have, and would tests for specific allergens help?
- Should we recheck it, and when?
- Does a low result matter for me, given my health history?
- Would it make sense to look at my other immune markers, such as IgG, IgA and IgM?
Questions people ask
Does a normal total IgE mean I'm not allergic?
No. Total IgE can be normal in people who are allergic to specific things. The maker of the ImmunoCAP test says about 30% of people present with raised specific IgE and a normal total, and it advises against using total IgE alone to screen for allergy. Tests for specific allergens, along with your symptoms, give a clearer picture.
Why is my lab's range different from the one here?
Labs use different assays and different groups of healthy people to set ranges. For adults, Labcorp lists 6-495 IU/mL, while ARUP lists up to 214 kU/L. Those units are the same number. Use the range printed on your own report.
How do I convert between units?
IU/mL and kU/L are the same number, so 100 IU/mL is 100 kU/L. If a lab reports in ng/mL (or ug/L), divide by about 2.4 to get IU/mL, because one unit of IgE is about 2.4 ng. For example, 240 ng/mL is about 100 IU/mL.
Show the science and sources
Units
- 1 IU/mL = 1 IU/mL
- 1 IU/mL = 1 kU/L
- 1 IU/mL = 2.4 ng/mL
Open the Total IgE unit converter
For clinicians and researchers
Total IgE is usually measured by fluoroenzyme immunoassay (Labcorp and ARUP both use Thermo Fisher ImmunoCAP). Serum IgE is the least abundant antibody class, and most IgE is bound to mast cells and basophils, so the serum level reflects allergic burden only loosely. Thermo Fisher's interpretation guide says about 30% of people present with raised specific IgE and a normal total (company data on file), and advises against screening with total IgE; it also notes that total IgE ranges depend on age and that the lab's own range should be used. IgE units are tied to the WHO International Reference Preparation for Human IgE, where one unit is about 2.4 ng, and 1 kU/L equals 1 IU/mL (VALIDA review). Reference intervals differ widely by assay and population. Labcorp lists 6-495 IU/mL for ages 17 and over, while ARUP lists 214 kU/L or less for ages 18 and over. In a Finnish hospital cohort of 2,431 children with total IgE above 1,000 kU/L, at least 82% had an atopic diagnosis, and non-atopic causes (mainly graft-versus-host disease and inborn errors of immunity) accounted for about 2%. IgE deficiency (under 2.5 IU/mL) has been associated with solid tumors, autoimmune disease and inborn errors of immunity in specialist-clinic and population cohort studies. These are associations in selected groups and do not show cause.
LOINC 19113-0 (primary), 2462-0, 76488-6. Specimen: serum-or-plasma.
Sources
- Immunoglobulin E, Total (test 002170), Labcorp
- Immunoglobulin E (test 0050345), ARUP Laboratories
- Allergy Blood Test, MedlinePlus (National Library of Medicine)
- Food Allergy Testing, MedlinePlus (National Library of Medicine)
- VALIDA project: Validation of allergy in vitro diagnostics assays (Tools and recommendations for the assessment of in vitro tests in the diagnosis of allergy), Advances in Laboratory Medicine (2020)
- ImmunoCAP Specific IgE blood test results: Interpretation (respiratory results interpretation guide), Thermo Fisher Scientific (Phadia) (2023)
- The Aetiology of Elevated Total Serum Immunoglobulin E in Children, Acta Paediatrica (2025)
- IgE deficiency (<2.5 IU/mL) in children: Clinical insights from a population-based study of 123,393 subjects, Pediatric Allergy and Immunology (2025)
- Characteristics of patients with low serum IgE levels and selective IgE deficiency: Data from an immunodeficiency referral center, Clinical Immunology (2025)
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.