How to test for house dust mite allergy: the difference between skin prick tests and specific IgE
The two common tests each suit different situations, and results need to be interpreted alongside symptoms.
Skin prick test
A small amount of standardised allergen extract is placed on the skin of the forearm, and a prick needle lightly pricks the surface of the skin. The wheal and redness reaction is observed after about 15 to 20 minutes. The advantages are that it is quick, visual and relatively low cost. Before the test, you need to stop medicines such as antihistamines that may affect the result, as instructed by the doctor. It is not suitable when there is widespread skin damage.
Serum specific IgE test
This is a blood test that measures the level of IgE antibodies against a specific allergen in the blood. It is not affected by skin condition or medicines, so it suits people whose skin is in poor condition or who cannot stop their medicines. Results are given as a grade or a number, and need to be judged together with age, exposure history and symptoms.
How to read the results correctly
A positive test only means that sensitisation to that allergen is present in the body. It does not mean symptoms will definitely appear. On the other hand, a negative result cannot completely rule out clinical allergy. What really matters is whether "symptoms match exposure". So when you see a doctor, tell them honestly when and where symptoms happen and what triggers them. The doctor will decide whether testing is needed and which method to choose. Whether treatment is needed after sensitisation is found, and how to treat it, is also decided by the doctor after assessment.
This article is for public education and for general information only. It is not medical advice. Please follow your doctor's instructions.
This article is for general information only and is not medical advice. If your symptoms affect daily life, please see a doctor.