IgE optimal range and reference range
Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026
Sera's bands for IgE:
- Optimal 0 – 100 IU/mL (0 – 100 kU/L); sufficient 100 – 214 IU/mL (100 – 214 kU/L); out of range below 0 or above 214 IU/mL.
Evidence grade: Published reference interval. A band that primarily reflects a published adult laboratory or population reference interval. It is not necessarily applicable to every assay or laboratory.
All units
| Unit | Optimal | Sufficient | Out of range |
|---|---|---|---|
| IU/mL | 0 – 100 | 100 – 214 | below 0 or above 214 |
| kU/L | 0 – 100 | 100 – 214 | below 0 or above 214 |
What the evidence says
Says whether the immune system is skewed toward allergy, not what someone reacts to — that needs specific IgE. Higher in atopic eczema, asthma and parasitic infection, and markedly raised in allergic bronchopulmonary aspergillosis. A normal total does not exclude a specific allergy. Adult upper limits vary a great deal by laboratory: NHS laboratories use about 81 to 120 kU/L, ARUP uses 214 kU/L and Labcorp 495 IU/mL. The acceptable band ends at ARUP's 214; the optimal edge of 100 sits between the two UK limits and has no published threshold of its own. kU/L and IU/mL are the same number.
Sources
- Immunoglobulin E — ARUP Laboratories, 2026 · Laboratory / reference-interval sourceTotal serum IgE reference interval at 18 years and older: 214 kU/L or less. This is the nearest published limit to Sera's sufficient upper edge of 200. Test directory page as opened in October 2026.
- Total IgE — Oxford University Hospitals NHS Foundation Trust, Immunology Laboratory, 2026 · Laboratory / reference-interval sourceAdult normal range for total IgE: 5 to 120 kU/L. The nearest UK limit above Sera's optimal upper edge of 100. Page last reviewed 6 July 2026.
- Total IgE — York and Scarborough Teaching Hospitals NHS Foundation Trust, Laboratory Medicine, 2026 · Laboratory / reference-interval sourceAdult total IgE below 81 kU/L, quoted from the Protein Reference Unit; below 75 from 15 years to adult. The nearest UK limit below Sera's optimal upper edge of 100. Test directory page as opened in October 2026; it carries no date.
What Immunoglobulin E (IgE) measures
The antibody class behind immediate allergic reactions and the response to parasites.
Total IgE says whether the immune system is skewed toward allergy, not what someone reacts to — that needs specific IgE testing. It runs higher in atopic eczema, asthma and parasitic infection, and is markedly raised in allergic bronchopulmonary aspergillosis. A normal total does not exclude a specific allergy. IU/mL and kU/L are the same scale.
Related autoimmune markers
- Antinuclear Antibody (ANA) — Screen
- Anti-CCP (Cyclic Citrullinated Peptide)
- tTG IgA (Tissue Transglutaminase IgA)
- EMA IgA (Endomysial Antibody IgA)
- Total IgA (Immunoglobulin A)
- Complement C3
- Complement C4
- Immunoglobulin G (IgG)
- Immunoglobulin M (IgM)
- Anti-Mitochondrial Antibody (AMA)
- Anti-Smooth Muscle Antibody (ASMA)