Specimen requirement

Adult patient:

  Clotted blood tube (Serum gel separator clot activator tube)

Minimum blood volume: 5 mL

Paediatric patient:

Paediatric clotted blood tube

Number of vials: 2

Minimum blood volume: 1.6 mL

Authorisation code required

No

24 Hr available service

No

Method

Immunoassay

Reference interval

(Source: from manufacturer's kit insert)

Clinical indication

Differentiating the allergic individual from non-allergic patients with symptoms of sneezing, wheezing, and itching

Result interpretation

Significantly elevated IgE levels are seen in most patients with disorders such as allergic rhinitis, extrinsic asthma, urticaria, and atopic eczema.

IgE levels may also be useful to the peadiatrician in patient care and follow-up since there is evidence that elevated serum IgE levels in young children are predictive of the subsequent development of allergic disease.

Elevated IgE values are also commonly found in parasitic diseases, some cases bronchiolitis and bronchopulmonary aspergillosis, and some types of immunodeficiency disease (Wiskott-Aldrich syndrome, DiGeorge syndrome and Hyper-lgE syndrome).

There is a large overlap between atopic and non-atopic individuals which limits the value of this test. Not all allergic patients exhibit elevated serum total IgE levels. Since not all atopic reactions are IgE-mediated, a total IgE result in the reference range should always be interpreted in light of other clinical observations.

Tests for allergen-specific IgE may clarify the finding of an elevated total IgE result.

Measurement of uncertainty

See table.

Frequency of measurement

1 - 2 weeks