Question

Which test is mostly favoured for testing allergy, prick test or blood test? Why?

Answer 1

Allergy testing is done to confirm or rule out allergies and thereby reducing the adverse reactions and limit unnecessary avoidance and medications. Correct allergy diagnosis, counselling and avoidance advice based on valid allergy test results is very important and helps in reducing the incidence of symptoms, need for medications and can also improve the quality of life.

Complete answer:
According to National Institute of Health guidelines for the diagnosis and management of food allergy and diagnosis and management of asthma recommends that either allergy blood testing or skin prick testing is reliable to determine allergic sensitization.

For an allergy blood test, a sample of the patient's blood is sent to the laboratory for analysis which then measures the presence of IgE antibodies to specific foods, pollens, mites, animals, insects and other environmental factors to determine if the patient has allergies. These tests are not affected by the use of antihistamines and can be done in people with extensive rashes that prevent them from using skin prick tests. This test should be performed with more caution and care.

For a skin prick test, a patient is pricked with a series of needles that contain extracts of allergic triggers. The doctor then looks for strong reactions like welts or red bumps to determine if the patient has allergies. The advantage of this method is that the person may find an acute allergy with specially trained healthcare staff available to stop life-threatening allergic reactions such as an unexpected anaphylactic reaction. It also allows the person to be prescribed tools for intervention needed if anaphylaxis ever occurs again, like a mobile epinephrine pen. It is also cheaper compared to a blood test and the results can be seen immediately.

Therefore, we can conclude that the Prick test is mostly favoured for testing allergy than the IgE blood test.

Note: IgE is the abbreviated form for "immunoglobulin E", which is the antibody that triggers food allergy symptoms. Epinephrine that is used as an intervention in skin prick test acts quickly to vasoconstriction, thereby increasing the blood flow to vital organs, relaxing the smooth muscles in the airway, allowing the patient to breathe until the emergency services arrive.