Total Serum IgE (Immunoglobulin E / Allergy & Atopy Screen)
Also known as: Serum IgE, Allergy Blood Test, Total Immunoglobulin E, Atopy Screen
Parameters Measured in the Report
A breakdown of individual biomarkers and biological reference intervals typically found in your report:
| Biomarker | Standard Range | Unit | What It Means |
|---|---|---|---|
Total Serum IgE (Serum IgE) | Normal Adults: < 100–150 (Allergic Atopy: > 150–1,000+ Parasitic / ABPA: > 1,000–5,000+) | IU/mL (or kU/L) | Total circulating Immunoglobulin E; elevated in atopic allergy, allergic asthma, eczema, and parasitic infections. |
* Note: Reference ranges may vary slightly between testing instruments and reagent kits. Always refer to the reference interval printed on your specific pathology report.
Clinical Focus
Total concentration of Immunoglobulin E (IgE) antibodies circulating in blood serum.
Sample & Specimen
Venous blood (Serum tube)
Fasting Protocol
No fasting required. Maintain regular diet and fluid intake.
Turnaround Time
12–24 hours
What Is This Test?
Why Did Your Doctor Order This Test?
Physicians routinely prescribe the Total IgE in the following clinical scenarios:
How to Prepare Before Your Test
- No fasting or special preparation required.
- Antihistamine medications do not alter total serum IgE concentrations (unlike skin prick tests, which require stopping antihistamines).
Understanding Your Results
What higher or lower readings generally mean in clinical practice:
If Values Are Higher Than Normal
Elevated Total IgE (>150–500 IU/mL) confirms an active atopic allergic constitution, prompting specific allergen panels (Skin Prick Testing or Specific IgE ImmunoCAP) to pinpoint the exact environmental or food triggers. Massive elevations (>1,000–5,000+ IU/mL) raise suspicion for Allergic Bronchopulmonary Aspergillosis (ABPA), invasive parasitic infections, or Hyper-IgE (Job’s) syndrome.
If Values Are Lower Than Normal
Low Total IgE (<20 IU/mL) indicates a very low likelihood of IgE-mediated allergic disease, suggesting that chronic rhinitis or asthma symptoms may be non-allergic (vasomotor) or intrinsic.
Frequently Asked Questions
Does a high Total IgE test tell me what specific food or pollen I am allergic to?
No. Total IgE only confirms that your immune system is in an "allergic/reactive mode." It does not name the specific culprit. Once Total IgE is confirmed high, doctors order "Specific IgE" tests or skin prick tests against specific dust mites, cat dander, molds, or foods.
Do antihistamine allergy pills affect my Total IgE blood test?
No. Antihistamines block histamine receptors in your tissues, but they do not alter the amount of IgE antibody circulating in your bloodstream. You do not need to pause your antihistamines for a blood IgE test.
Related Laboratory Tests
Tests frequently prescribed together or used as follow-up investigations:
Medical & Diagnostic Disclaimer
This guide is published for educational and patient informational purposes only. It is not a substitute for professional medical evaluation, diagnosis, or clinical advice.
A laboratory result that falls slightly outside standard statistical reference intervals does not automatically indicate disease; conversely, a normal result does not guarantee the absence of medical conditions. Only your attending physician can interpret lab findings in the context of your medical history, physical exam, and symptoms.