Blood Spot Test
When an allergic reaction occurs, the immune system reacts by releasing cells called antibodies. The foods and inhaled particles that provoke the release of antibodies are called allergens. Two commonly produced antibodies are IgG (immunoglobulin G) and IgE (immunoglobulin E).
Conditions related to IgG allergies:
IgG allergic reactions occur over several hours or days. With an IgG allergic reaction, IgG antibodies attach themselves to the allergen and create an antibody-allergen complex. These complexes are normally removed by special cells in the liver and spleen called macrophages, but if they are present in large numbers and the allergen continues to be consumed, the body isn't able to remove them fast enough. These allergen-antibody complexes accumulate and are deposited in body tissues, causing the release of inflammation causing chemicals which contribute to a variety of health problems:
Headaches and high blood pressure: may result from deposition of antibody-allergen complexes in blood vessels.
Mood disorders: Deposition of antibody-allergen complexes in nervous system tissues may contribute to hyperactivity, depression, anxiety, inability to concentrate and other mood disorders.
Asthma and recurring respiratory infections: Deposition of antibody-allergen complexes in lung tissue can cause a variety of respiratory problems.
Eczema and other skin conditions: may result from deposition of antibody-allergen complexes in the skin.
Joint pain: may result from deposition of allergen-antibody complexes in joints.
Runny noses and puffiness around the eyes: can result from allergic reactions.
Why Test For Food Allergies?
Because IgG allergies are delayed hours or days after exposure and can be caused by multiple foods, they are virtually impossible to identify without testing. IgG allergy testing requires a simple finger poke, either at home or in your practitioner's office. The blood from the finger poke is used to saturate three test strips which are left to dry. The laboratory tests these dried blood spots for IgG antibodies to a variety of different foods
Talk to your health care provider about getting a food allergy test done.
What Do Allergy Test Results Mean?
IgG Delayed Hypersensitivity Reactions
IgG reactions develop slowly, up to several hours or days after exposure to a food allergen, so testing is often the only way of determining which foods are the culprits. The allergy test report graphs your immune response to each of the foods tested. Reactions are categorized as no, low, moderate or high.
Generally speaking, practitioners are most concerned with the moderate and highly reactive foods. They may suggest eliminating moderately reactive foods from your diet for a certain amount of time, and highly reactive foods for a longer period of time. It is often possible to reintroduce these foods after the elimination period has ended and without symptoms recurring. However, it is important to follow your health practitioner‘s instructions regarding reintroduction of potential allergens.
Eliminating food allergens sometimes results in withdrawal symptoms like headaches, tiredness, irritability and hunger. Serious cravings for the eliminated foods are also common. Unfortunately, it is often the foods you are most allergic to that you crave the most! Knowing these cravings and symptoms are temporary, hopefully makes them easier to bear.
And lastly, there is a condition called leaky gut syndrome that can promote the development of food allergies, and can itself be caused by food allergies. An overload of antibody-allergen complexes causes inflammation in the lining of the gut, which causes the gut to leak. This leaky gut allows more antibody-allergen complexes to escape into tissues, which provokes more allergic reactions to food. Thus, anyone with leaky gut should be tested for food allergies and anyone with a lot of allergies may need to be treated for leaky gut. Therefore, your health care practitioner may suggest treatments for your digestive system in addition to any recommended dietary changes.
It is important to remember that a low IgG reaction to a particular food does not necessarily mean that food is safe to eat. For example, someone with a low IgG response to peanuts could still experience a life-threatening IgE reaction to peanuts. IgG reactions are very different from the immediate IgE hypersensitivity reactions.
What does No Reaction really mean?
Allergy tests offer a snapshot of the immune response to various foods. However, sometimes a no reaction result is recorded when an individual knows he/she is intolerant of a specific food. There are several reasons why this can occur. Foods that have not been consumed for two or three weeks prior to the test may not provoke an allergic response because there are no allergens to react to. In other words, if you don't eat it, you won't produce antibodies to it, so no reaction occurs. (The exception to this is if there is cross-reactivity with another food group).
Another possibility is that the reaction you experience is actually an intolerance, not an allergy. Food intolerances may mimic the symptoms of a food allergy but are not the direct result of an antibody-antigen reaction. For example, lactose intolerance is due to a deficiency in the enzyme lactase, the enzyme responsible for the digestion of the milk sugar lactose. Adverse reactions to food additives may also be defined as food intolerance. Sometimes a lack of digestive enzymes or stomach acid can result in a food intolerance. It is also possible, based on a previous negative episode with a specific food (e.g. food poisoning) to have a physical reaction to that food, because of the negative experience associated with it.
**Description courtesy of Rocky Mountain Analytical