YOUR ALLERGIES CENTER

Various testing methods are available to test for allergies, which include blood or skin testing.

1. TESTING FOR FOOD ALLERGIES
2. ALLERGY TESTING - METHODS COMPARISON
3. ALLERGY TESTS AVAILABLE AT THE CLINIC

TESTING FOR FOOD ALLERGIES

Conventionally accepted medical approaches of assessment for this condition may include various tests such as:

• Blood tests - RAST and Elisa food testing for IgG + IgE food antibodies


• Skin tests - small punctures made with needles containing tiny amounts of allergens


• Challenge or provocative testing - your provider may place food extracts under your tongue or inject them

ALLERGY TESTING - METHODS COMPARISON

1. The elimination diet and food challenge test is used to identify food allergies. The elimination diet involves removing specific foods or ingredients from your diet that you and your doctor suspect may be causing your allergy symptoms. (Common allergy-causing foods include milk, eggs, nuts, citrus, wheat and soy.) Your doctor will supervise this diet over a few weeks.

You will need to carefully record any symptoms that occur when you eat each of these foods. If your symptoms return after eating the food, the diagnosis can usually be confirmed. You will be asked once again to eliminate the foods that have been identified as causing symptoms to see if the symptoms clear up. You will also need to keep a food diary to record the foods you are eating. If you remove a certain food and the symptoms go away while following this diet, your doctor can usually identify that food as the cause of your problems.

After following the elimination diet, your doctor will ask you to gradually reintroduce the foods you were avoiding into your diet, one at a time. This process helps link symptoms to specific foods.

This is not a foolproof method. Psychological and physical factors can affect the diet's results. For example, if you think you're sensitive to a food, a response could occur that may not be a true allergic one.

Before making significant changes in your diet, always seek the advice of your doctor. If you randomly remove foods from your diet, you may not have a balanced diet -- and a lack of some nutrients can cause other health problems. You may also become frustrated because it may seem that everything you eat is causing a reaction. If you've had a severe (anaphylactic) reaction to certain foods, this method can't be used.

2. The double-blind, placebo-controlled food challenge (DBPCFC) is considered the GOLD STANDARD in diagnosing food allergies. This procedure can be somewhat invasive (requiring subjects to have food antigens administered via a nasogastric tube), is time consuming and potentially dangerous if the reaction is severe. In addition, the DBPCFC is only able to confirm specific food reactions based upon patient history and prior evaluation.
3. Conventional skin testing and RAST tests measuring IgE-mediated reactions cannot guide physicians as to the potential for delayed, non-IgE-mediated reactions. In one study, researchers surmised that because an IgG subclass was involved in late-onset reactions, patients exhibiting delayed bronchial allergic reactions failed to show positive skin test reactions or RAST results to a specific allergen. A recent study by Jahn-Schmid et al, demonstrated the increased sensitivity of ELISA testing in detecting food allergies when compared with RAST testing.

Skin testing, while a valuable indicator of IgE mediated reactions also has its limitations. This diagnostic test should ideally be performed by a skilled physician as it may trigger life-threatening symptoms such as anaphylaxis.

4. Antibody Testing with ELISA - a detailed and comprehensive analysis is crucial for the clinician to make accurate, precise diagnoses of food and environmental allergies. With the Allergy Antibody Assessment, IgE and IgG levels are assessed using an Enzyme-Linked Immunosorbent Assay (ELISA). This advanced immunological procedure uses an enzyme binding process to detect antibody levels, and has been hailed as a "safe, economical, and highly sensitive test".

Because the ELISA method identifies antibodies associated with both immediate and late-onset, delayed reactions, it offers a clear advantage over other conventional food antibody assessments. (Adapted from the GSDL allergy assessments). We provide this test in our clinic.

• Previous
• Next