Skin prick test

Skin prick Testing(SPT) is one of the most commonly used diagnostic procedures in allergy, as it is simple, safe,cost effective, and delivers quick results. All skin prick tests must be based on a careful and detailed clinical history, as screening or random SPT may be highly inaccurate and misleading.

SPTs take about 15-20 minutes, and can be safely performed on children of any age, as long as they have not taken antihistamines for a few days prior.

A skin prick test involves introducing a very small amount of a suspected allergen into the surface layer of the skin, usually on the forearm. The skin is then observed for 15-20 minutes, and any resulting local reactions(lumps or wheals) are marked as potential allergic responses.

Pulmonary Function Tests

Pulmonary Function Tests, also called lung function tests or spirometry, are simple and non-invasive tests that measure how well your lungs are working. The tests determine whether or not you have any airflow obstruction or restriction, and whether or not your lung function improves following asthma therapy. Like measuring blood pressure in a person with hypertension, or blood sugars in someone with diabetes, PFTs are essential to diagnose and monitor conditions like asthma and chronic obstructive pulmonary disorder (COPD).

Your allergist will determine if you require spirometry, and your results will be immediately available to review with the team.


Oral Food Challenges (OFC)

If your history suggests a possible food allergy, your allergist may wish to perform an oral food challenge (OFC) to confirm or refute this.

OFC involve eating small and then increasing amounts of a food you may be allergic to under observation in a safe, controlled setting. Experts agree that OFC are essential for the accurate diagnosis of food allergy, as both skin and blood testing have an unacceptably high rate of false or clinically-irrelevant positive results.

OFC carry a risk of reaction, including anaphylaxis, however the Snö team of allergists and nurses have extensive training and experience with food challenges, and will only recommend this procedure when appropriate or necessary for your care.

Intradermal allergy test

Intradermal (ID) testing is less commonly needed, but can behelpful in the diagnosis of suspected drug, venom, or vaccine allergies. With ID testing, which is approximately 1000x stronger than skin prick testing, very small amounts (0.02ml or 1/1500 of an ounce) of the potential allergen are injected with an extremely tiny needle into the surface layer of the skin, much like a screening test for tuberculosis. The injection site is then monitored for a local reaction for 20 minutes, which may suggest an allergic response.

ID testing is not generally used for suspected food or environmental allergies.

Drug challenges

Like oral food challenges, there are some situations where the best and most accurate way to confirm or rule out a suspected drug allergy is by performing a drug challenge. This may involve oral administration of a suspected drug allergen, such as penicillin, or a low-dose injection of a medication such as lidocaine or another local anesthetic used in dental work.

Following a drug challenge, the patient is monitored for a possible allergic reaction, usually for an hour, and of course would be treated appropriately should any concerning symptoms develop.

Blood allergy test

Allergy blood tests, or specific IgE tests, can be used instead of, or to compliment allergy skin prick tests.

Like skin prick tests, allergy blood tests are safe and accurate, if selected based on a careful and appropriate clinical history.

Allergy blood tests measure the amount of IgE antibodies (a type of antibody responsible for allergic reactions) specific for a particular allergen in blood. High levels of specific IgE may mean you have an allergy, and your allergist will use these results in combination with your clinical history to help establish your diagnosis and most appropriate management plan.