Immunoglobulin E (IgE)

Sample
- The best sample is fresh serum.
Indication
- Used to detect allergic diseases.
- Advised when the patient have:
- Itching of the skin, and itching of the eyes.
- Urticaria and hives.
- Asthma and difficulty in breathing.
- Skin diseases like eczema.
- A cough, congestion.
- Sneezing.
- Persistent diarrhea, nausea, and vomiting.
Pathophysiology
- IgE exists as a monomer form with a molecular weight of 190,000 and is 7S.
- It has an extra domain in the constant portion.
- It has:
- Two epsilon (ε) heavy chains.
- One pair of kappa (κ) or lambda (λ) chains.
- It’s Fc region binds strongly to the receptors on the mast cells and basophil along with antigens.
- It is 0.004 % of the total immunoglobulins.
- Its half-life is 2 days.
- It is mainly involved in type 1 hypersensitivity reaction.
- It cannot activate the complement system via the classical pathway.
- It is present in the serum of a healthy person is extremely low concentration.
- It attaches to the receptors on basophils and mast cells.
- There are low-affinity receptors present on the surface of B-lymphocytes and eosinophils.
- It can not cross the placental barrier.
Normal Value
Source 1
Age | IU/mL |
Cord blood | At term ∼1% of the maternal value |
0 to 4 days | <1.5 |
5 days to 12 month | <15 |
1 to 5 year | <60 |
6 to 9 year | <90 |
10 to 16 year | <200 |
>16 year | <100 |
Adult | 3 to 423 |
- To convert into SI unit x 1.0 = kIU/L
Another source
- 150 ng/ml on the topic (non-allergic) person.
- or .002 to 0.2 mg/dl
- Values vary because of the methodology used.
The raised level is seen in:
- Allergic diseases like asthma, skin diseases.
- Parasitic infestation
- Multiple myeloma producing monoclonal IgE.
- Hyper IgE syndrome.
The decreased level is seen in:
- Agammaglobulinemia.