radioallergosorbent [RAST] testing

Introduction

In vitro test measuring IgE to a specific allergen. In general it is more expressive & less sensitive than skin testing.

Clinical significance

In general, in vitro RAST testing is not as sensitive as skin testing.

It is useful in patients:

• who have been taking antihistamines in whom no positive histamine responsiveness can be induced in the skin
• with primary skin disorders that make allergen skin testing impractical (i.e., generalized eczema)

Procedure

• allergen protein is chemically coupled to a solid-phase substance
• patient serum is incubated with the solid support
• the solid support is washed free on non-binding materials
• the washed support is incubated with radiolabelled anti-IgE antibody
• wells are counted (presumably various dilutions of patient serum) & compared against a standard curve prepared from known amounts of allergen-specific IgE

More general terms

• allergen serology

More specific terms

• Coffee bean IgE Ab RAST class in serum
• Coffee IgE Ab RAST class in serum
• Japanese Cedar IgE Ab RAST class in serum
• Sweet Vernal grass IgE Ab RAST class in Serum

Additional terms

• allergen skin testing