IgE Lab Test

RAST test; Radioallergosorbent test; Allergy screen; Allergen-specific IgE antibody test

Clinical Definition of IgE

Allergies are an extensive, widespread, condition in our society. So much so that 40% of children and 30% of adults in the US find themselves being vulnerable to allergies. 

The long, list of types of allergies people face is indeed exhaustive. For instance, few tend to have an allergy to drugs (medicines). Even though the number is very few, the allergy is mainly caused due to the side effects the medicine can have on an individual which is highly dependent from one person to another. The most common of all we see is the intolerance people have towards particular food items such as dairy, eggs, peanuts, shellfish and even milk which is extensive in children.

At times, insects such as wasps, bees, and hornets can be troublesome for a few in more than one ways. One of the allergies that can pose a severe health risk is the allergy to latex. Latex is the milky fluid that is observed in trees and plants when they are cut and exposed to air. Latex, from the rubber tree, also happens to be a vital source of natural rubber. Individuals, who tend to be allergic to latex, will distance themselves from gloves and balloons.

Other kinds of allergies, which are well-known, includes an allergy to pets. The allergy is predominantly because of the fur. Pollen allergies are seasonal but very common. More commonly known as hayfever, from an expert point of view, they are known as seasonal allergic rhinitis. Mold allergy is another type that involves being allergic to fungi and mildew.

So, it is quite evident from the aforementioned paragraphs that, we all don't tend to share the same kind of allergy, or even, fortunately, we might not even be allergic to any of these. But, it can clearly be understood that allergy, as a strong dislike for something could be purely dependent on an individual. 

What you are allergic to, tends to be perceived as a foreign invader by your immune system, which is the reason it reacts in a different way.

An allergy, in a crude way, could be simply described as an overreaction by our immune system. The antibody named Immunoglobulin E, which is more commonly know as IgE is produced by the immune system for allergens, and these antibodies travel to the cells to instigate them to release a chemical which will result in an allergic reaction.

IgE is a protein associated with allergic reactions. It is normally found in very small amounts in the blood. IgE is produced by plasma cells. It is an antibody that functions as part of the body’s immune system. It is released by the immune system to fight against the foreign bodies and allergens that enter the body. IgE antibodies are generally found in the skin, lungs and mucous membranes of the body. They cause reactions as soon as they detect the presence of any environmental allergen such as pollen, fungus, spores or dander. The body perceives the potential allergen as a foreign substance and produces a specific IgE antibody that binds to specialized mast cells in the skin, respiratory system, and gastrointestinal tract, and to basophils in the bloodstream. During the next exposure, the attached IgE antibodies recognize the allergen and cause the mast and basophil cells to release histamine and other chemicals resulting in an allergic reaction. People with allergies often have elevated IgE levels. IgE plays an important role in conditions such as asthma and various allergies, atopic dermatitis, certain types of cancer and is mostly associated with type 1 hypersensitivity. IgE levels are also elevated in children with parasitic infections.

 

When do you expect results?

24 to 36 Hours

 

Why Get Tested?

IgE serum test determines levels of allergen-specific immunoglobulin E (IgE) in the blood to help diagnose an allergy to a particular substance. IgE is one of the five classes of antibodies. Antibodies are proteins created by the immune system that attack antigens, such as bacteria, virus, and allergens and neutralize the foreign objects that find entry into the body. IgE antibodies are found in the lungs, skin, and mucous membranes. They are associated mainly with allergic reactions (when the immune system overreacts to environmental antigens such as pollen or pet dander) and parasitic infection.

 

Reason to take IgE Test

Allergies are the direct indication of the alarming level of IgE in our blood. Even though the allergies are most commonly not fatal, they can easily have a substantial effect on us nevertheless. They can have grim implications if the IgE level in the blood is not taken care of accordingly and in the prescribed period of time.

Hives: These are itchy and often lumpy rashes that can be observed on the person's skin. Urticaria is the medical term and these rashes can easily spread over someone's body. Overly exposed to the sun, food intake which is intolerant to the system are some of the causes for hives. Hives are one of the sure-shot ways of indicating elevated levels of IgE in the blood.

Sneezing; To sneeze once in a while is easily distinguishable from the sneezes that are erratic, uncontrollable and result in watery eyes and stuffy runny nose. The duration and the frequency this problem arises are the indications of inappropriate levels of IgE in the system.

Nasal congestion: Also known as stuffy nose, nasal obstruction, and nasal blockage, this condition can be observed when the membranes lining the nose swells because of inflamed blood vessels. The blood vessels inflame as result of a biological response to pathogens, damaged cells or irritants.

Tight throat: This also goes by the name swollen throat which is usually caused because of increased levels of histamine, IgE levels and other chemicals throughout the body.

Trouble breathing: People suffering from hyper IgE syndrome usually suffer from recurring bacterial pneumonia. More commonly observed in children, patients with high IgE have a higher possibility of having the lung tissue damaged, and it can also result in chronic lung disease.

Dermatitis: This medical condition in which the skin can become red, swollen and itchy usually signifies an upsetting level of IgE in the blood. Sometimes people who are prone to dermatitis will also be vulnerable to food allergy, asthma, and allergic rhinitis.

Eczema: Recent research does point out that eczema, which is more commonly observed in children, may not be because of an allergy. But what it does point out is that abnormal functioning of the immune system and genetics play a crucial role in this regard. Hence this condition must not be overlooked.

Abdominal pain; The frequency and the duration for which this usually occurs in children indicates a highwr level of IgE in blood.

Vomiting and diarrhoea: Similar to dermatitis, patients who suffer from hyper IgE along with suffering from vomiting and diarrhoea tend to be intolerant to certain food and show other common hyper IgE symptoms.

Other symptoms include:

Red itchy eyes

Coughing

Asthma

Itching and tingling in the mouth

 

Symptoms may be seasonal (as with allergies due to pollen or moulds) or year-round (as with food allergies).

 

Preparations Needed for IgE Test

No Fasting Required.

No other special preparations required.

 

Sample Required?

Specimen type: Serum (Blood Sample)

Specimen collection procedure:

Venipuncture (Collection of blood from a vein, usually from the arm)

Understanding results of IgE

Reference RangeInterpretation
Upto 60 IU/ml1-5 years
Upto 200 IU/ml10-15 years
Adult0-378IU/ml
Upto 90 IU/ml6-9 years
0 to 100 IU/mlMale
Upto 15 IU/mlInfants in first year of life
0 to 100 IU/mlFemale

‘*A Reference range is a set of values which helps the healthcare professional to interpret a medical test. It may vary with age, gender, and other factors. Reference ranges may also vary between labs, in value & units depending on instruments used and method of establishment of reference ranges’

References

  1. https://kidshealth.org/en/parents/test-immunoglobulin-e.html
  2. http://pediatrics.aappublications.org/content/136/Supplement_3/S230.1
  3. medlineplus.gov/labtests/allergybloodtest.html
  4. kwww.ncbi.nlm.nih.gov/pubmed/9301170