Skin Prick Testing (SPT) is the most commonly performed allergy test. It is used to test for Immunoglobulin E (IgE) type of allergy to environmental allergens such as house dust mites, pollen, animal dander and also food allergens such as shellfish, cow’s milk, soy, wheat, peanuts, treenuts, eggs and fish.
Standardised extracts of the many various allergens are available in our hospital. One droplet of each extract is placed on the inner aspect of the forearm about 3cm apart and a specially modified lancet is used to prick the surface of the skin through the droplet. Care is taken not to draw any blood. A swelling of at least 3mm in diameter is a positive reaction. This test can be performed within the same clinic visit and the result can be read at around 20 minutes after the test is performed.