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Also known as  Comprehensive Food Intolerance IgG panel 188 tests
The RAST test or radioallergosorbent test is undertaken to determine if a person is allergic to a certain substance or a group of substances.
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The RAST test checks for an antibody known as immunoglobulin E (IgE) to measure the immune system's reaction to specific allergens or a range of allergens.

What is a RAST test?

A laboratory blood test used to confirm a person's allergies is known as a RAST test. It helps determine the presence of antibodies for specific substances to which the individual may have an abnormal sensitivity.The human body produces proteins or antibodies in response to certain allergens or foreign substances. If you have an allergy, your immune system will produce IgE in response to allergens, even if they are harmless. This often results in acute, chronic, or fatal symptoms. The RAST test is a sensitive, cost-effective, and safe procedure when conducted by an experienced professional.

What are the other names for the RAST test?

The RAST test is also known as a radioallergosorbent test. Many a time, it may also be referred to as an IgE allergy, immunoglobulin E, quantitative IgE, total IgE, or specific IgE test.

What are the test parameters included in a RAST test?

A RAST test reports findings on a grade scale of 0 to 6. The lower the value, the lesser the chance of an allergy. Positive or higher values indicate a greater likelihood of allergy.RAST tests can be of two types:

Specific IgE test: measures the amount of IgE the body produces in reaction to a specific allergenTotal IgE test: measures the amount of total IgE antibodies in the body

What does a RAST test measure?

A RAST test measures the presence of antibodies or IgE in the immune system. These antibodies trigger the release of certain chemicals in the body that cause an allergic reaction. When you are allergic to a particular substance, your immune system mistakenly recognizes the allergen or foreign substance as a threat. It then begins to synthesize IgE antibodies that specifically bind to the allergen and try to inactivate it.The results indicate whether or not the body reacts to one or many substances and are graded to indicate the severity of the reaction.

What’s the normal range of a RAST Test?

GrdaeIgE LevelComment
Grade 0<0.35 KUA/LNegative or Undetectable Level
Grade 10.35-0.7 KUA/LWeak Positive Level
Grade 20.7-3.5 KUA/LModerate Positive Level
Grade 33.5-17.5 KUA/LHigh Positive Level
Grade 417.5-52.5 KUA/LStrong Positive Level
Grade 552.5-100 KUA/LVery Strong Positive Level
Grade 6>100 KUA/LExtremely Strong Positive Level

Who should get a RAST test?

If you are allergic to pollution, dust, pet dander, or pollen, there are chances that you may develop a condition known as allergic rhinitis or hay fever. Some of the common symptoms are:

  • Constant headaches

  • Itchy, red or watery eyes

  • Sneezing or runny nose

  • Sore throat

  • Chronic cough or wheezing accompanied by shortness of breath

On the other hand, one or more allergen-specific RAST test is needed when you show certain signs and symptoms that are specific to the ingestion of a particular food or a group of foods. These may be milk, eggs, nuts, seafood, grains or pulses. Symptoms may arise within 30 minutes to 2 hours of consumption. These may be:

  • Gastrointestinal symptoms such as vomiting, diarrhoea, abdominal pain, cramps, or nausea

  • Respiratory reactions such as sudden wheezing, coughing, swelling of the vocal cords, tightness of the throat and chest, or a tingling sensation in the mouth

  • Skin conditions such as swelling of the face, lips or tongue, eczema (dry or peeling skin), and overall itching of the body

  • Cardiovascular reactions such as lightheadedness, chest pain, dizziness, pale skin, and breaking out in a sweat.

If you are allergic to certain fragrances, nickel, chemicals, detergents, or poisonous plants, you may need a RAST test. The common symptoms are:

  • Hives and swelling of the skin

  • Unexplained rashes or itching of the skin

  • Burning sensation or formation of blisters on the skin

Allergic reactions, in general, can range from uncomfortable congestion to a fatal anaphylactic shock. A healthcare professional may recommend a RAST test to help gauge your condition and recommend the correct line of treatment.

What are the preparations needed for a RAST test?

Since this is a simple blood test undertaken by a professional, no preparation is required. It is essential to ensure that you do not consume antihistamines for at least 3 days before undergoing the test as they may interfere with the test results. Speak with your physician or a healthcare professional for any doubts or queries you may have before undergoing the RAST test.

What is the type of sample required for a RAST test?

Professionals undertake a simple blood test to perform a RAST test. Usually, a sample of 0.3 mL of serum is needed per allergen. This blood sample is usually drawn from a vein on the arm.

Who performs a RAST blood test?

After you book a test online, highly trained, professional, and vaccinated eMedics from Orange Health will visit you in the comfort of your home. Our experienced medics will draw the required amount of blood from a vein in your arm while keeping your comfort in mind. They will then carry this sample back to our laboratory for further testing.

What should I expect during a RAST blood test?

A simple RAST test requires less than 5 minutes to perform. You can expect the following:

  • In the comfort of your home, you will be asked to be seated on a chair, while our eMedic will look for an accessible vein in your arm (venepuncture).

  • Blood will be drawn using a thin sterile needle after the area is disinfected. You may feel a small pinch.

  • The collected blood sample will be put in an air-tight vial or test tube.

  • A small piece of cotton or gauze will be placed on your arm to stop the bleeding.

  • After applying a small bandage on the area, the process will be completed.

Our experts keep your comfort in mind every step of the way.

What should I expect after my RAST test?

Your blood sample will be sent to our laboratory for further testing and evaluation. You can expect results sent to you or your healthcare provider within 5 days of the collection of the sample.

What are the risks of a RAST test?

Normally, a RAST test does not involve any risks or serious side effects. Some people may notice light bruising, soreness of the arm, or some bleeding in the area where the blood was drawn from. Normally, these symptoms subside on their own within a day or two.

When can I expect my RAST test results?

Normally, RAST test results take about a week. At Orange Health, you can expect your results 5 days from the day the sample was collected.

What do the results of a RAST test mean?

Elevated or positive levels of IgE may be indicative of an allergy but do not show how serious this allergy may be. A negative test result may imply that you are not allergic to a particular substance and the symptoms you are experiencing are the results of some other reaction.

We all have some IgE antibodies in our bodies. Since grading systems differ from laboratory to laboratory, it is advisable to seek the advice of an experienced healthcare professional to evaluate the results and correctly diagnose the condition. The treatment plan will depend on the severity of the condition.

What are normal RAST test results?

The results of a RAST test are normally provided in numbers ranging from 0.10 kU/L to 100 kU/L. Any value less than 0.35 kU/L indicates the unlikely sensitization to an allergen. You should keep in mind that the results of the RAST test do not determine the severity of a reaction. The results of the test are interpreted in conjunction with your medical history and the pattern of your allergic reactions. You must seek the advice of a healthcare professional for an accurate diagnosis.

What other tests might I have along with this test?

Other tests are usually not recommended with a RAST test.

How to book a RAST test at home?

Follow the below-mentioned steps to book a RAST test from the comfort of your home:

  • Log on to our website -

  • Choose the RAST Test from the lab test tab and click on "book now"

  • Fill in your details, such as your location, patient's full name, and address

  • Book the slot of your choice at your convenience

  • Our highly trained, professional, and vaccinated eMedics will be at your doorstep within a short while to conduct the test.

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