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How To Read Allergy Blood Test Results

How Should You Begin To Discover If You Have A Problem


The first step, unfortunately, often involves trying to convince your doctor to perform blood testing. Our healthcare model doesnt like to pay for tests unless they are absolutely necessary, and if your doctor doesnt agree with your suspicion you may find yourself in the dilemma of not being permitted to find out if you have a gluten problem.

If you cannot convince your doctor, yet you are very suspicious and concerned, you can find a doctor like myself who can help you to get tested. It will be without the financial support of your insurance company, but the testing is not financially prohibitive for most.

If you are fortunate enough to have the backing of your doctor, the next step is to confirm that a full panel is being run and not a single test. As we discussed above, there is more than one piece of data required to make a diagnosis and you need to ensure you are receiving a complete analysis.

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Identify The Cause Of Patient Symptoms For More Effective Treatment

Allergies, respiratory infections, and asthma often present with similar symptoms, making them difficult to differentiate. Being able to rule in or rule out allergies as the cause of your patients symptoms can help inform better treatment decisions and improve patient outcomes.

From individual allergen tests and component testing to regional environmental allergy test panels, Quest offers a comprehensive range of ImmunoCAP® IgE blood allergy tests to meet the full spectrum of patient needs.

Quick And Effective Tips To Remove Pet Dander

As we mentioned, pets with fur or feathers tend to shed dander and allergens. Unfortunately, with pets, you cannot get rid of dander completely. But here are some quick fixes to help reduce pet dander.

Steam clean: cleaning carpets, furniture, and curtains might help remove pet dander. Steam cleaning the floors also helps clean them deeply. You can also use a sticky lint roller to quickly remove pet dander from any type of surface.

Bath your pet regularly: when you bath a pet, the extra fur or skin flecks will get flushed down the drain.

Get a good air purifier: many pet owners think air purifiers are overrated, but that is not true. A HEPA filter can genuinely change your life and filter the pet dander from your homes air. A good pet air purifier will drastically change the quality of your life by helping you breathe and sleep better. It also helps keep the particular pet odor at bay.

Get professional help: if nothing helps and your allergies are getting worse, you need to get the air ducts cleaned by professionals. A professional air duct cleaning service will remove dander built-up and thoroughly clean the air ducts from allergens. This means removing any, and all types of pet dander from everywhere.

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Medications Can Interfere With Skin Allergy Test Results

Before scheduling a skin allergy test, bring your doctor a list of all of your prescription and over-the-counter medications. Some medications can suppress allergic reactions, preventing the skin testing from giving accurate results. Other medications may increase your risk of developing a severe allergic reaction during a test.

Because medications clear out of your system at different rates, your doctor may ask that you stop taking certain medications for up to 10 days. Medications that can interfere with skin tests include:

  • Prescription antihistamines, such as levocetirizine and desloratadine .
  • Over-the-counter antihistamines, such as loratadine , diphenhydramine , chlorpheniramine , cetirizine and fexofenadine .
  • Tricyclic antidepressants, such as nortriptyline and desipramine .
  • Certain heartburn medications, such as cimetidine and ranitidine .
  • The asthma medication omalizumab . This medication can disrupt test results for six months or longer even after you quit using it .

Allergy Skin Test Side Effects


The most common side effects of skin allergy testing is slightly swollen, red, itchy bumps . These wheals may be most noticeable during the test. In some people, though, an area of swelling, redness and itching may develop a few hours after the test and persist for as long as a couple of days.

Rarely, allergy skin tests can produce a severe, immediate allergic reaction, so its important to have skin tests performed at an office where appropriate emergency equipment and medications are available.

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Is There Anything Else I Should Know

Sometimes, a healthcare practitioner will look at other blood tests for an indirect indication of an ongoing allergic process, including a total IgE level or a complete blood count and white blood cell differential . Increases in these test results may suggest an allergy, but they may also be elevated for other reasons.

There Are Two Main Types Of Allergen Skin Testing Used To Help In The Evaluation Of Potential Allergies Skin Prick Testing And Intradermal Testing

Skin prick testing is minimally invasive and involves pricking the outer surface of the skin with either a commercial allergen extract or the fresh allergen if needed. Intradermal testing is slightly more invasive and involves a small injection of a solution containing allergen that is placed just underneath the surface of the skin.

These skin tests are done on areas of the body that generally contain a substantial number of allergy cells, such as the arm or the back, and they are read for results during your appointment about 15-20 minutes after being placed. At Allergenuity Health, we attempt to be as least invasive as possible while getting the information we need to best help you with your goals.

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Allergy Blood Test Results

A positive result means allergy-specific antibodies were detected in your blood. This is usually a sign of an allergy.

The blood test will reveal what exactly you are allergic to. However, you can test positive for something but never have had an allergic reaction to it.

A negative result means you probably do not have a true allergy. That means your immune system probably does not respond to the allergen tested. However, it is possible to have a normal allergy blood test result and still have an allergy.

Allergy blood test results should be interpreted with caution by an allergy specialist. Your doctor will also consider your symptoms and medical history when diagnosing a specific allergy.

What Is A Positive Skin Test Result

Allergy blood test | Allergy testing from blood test | Hypersensitivity testing | Allergenic test

A positive skin test involves the formation of a bump and redness . In addition to the allergens in question, skin testing is also performed with a positive control that should always cause a skin reaction, and a negative control, , that should not cause a reaction. A test is positive if the allergen causes a wheal 3 mm greater than the negative control, and if the skin has a response to the histamine, as well. It is important to know that individuals cannot undergo skin testing if they are using antihistamines, since this blocks the histamine-mediated reaction.

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What Causes The Allergies

Cats can cause allergic reactions in people but the exact causes of the irritation are not clear for everyone.

Some people may think hair or fur causes the allergies, but hair cannot cause irritation in humans.

Cat dander contains a protein known as the glycoprotein Fel d1,which is the main cause of allergies. Cat urine and saliva may havetraces of this protein, but not enough to cause irritation.

The dust and different pollens that may lodge in your cats fur may also cause allergies.

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How Is An Ige Blood Test Performed

An IgE blood test is done by inserting a needle into a vein in the arm or back of the hand, collecting a blood sample, and pulling it into a vial. The blood sample is sent to a laboratory to assess the response to different types of food allergens. Results can take a few weeks to become available. The results are given in numbers that range from 0.10 kU/L to 100 kU/L. Keep in mind that the results do not determine the severity of a reaction to a food allergen , only the level of antibodies produced after being exposed to the allergen.

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What Are The Benefits Of Blood Allergy Testing

While blood allergy testing is less common than skin prick testing, it does have certain benefits.

  • A blood test can be conducted while taking medication, whereas skin tests may require you to stop meds such as steroids and antihistamines for a few days.
  • Patients with skin conditions like eczema and psoriasis may not be able to tolerate a skin test.
  • Blood tests offer a safer alternative if you have severe reactions to allergens or anaphylaxis.
  • Patients with heart conditions or asthma may require a blood test.

What Does The Test Result Mean


An elevated allergen-specific IgE result indicates that the person tested likely has an allergy. However, the amount of specific IgE present does not necessarily predict the potential severity of a reaction. A person’s clinical history and additional medically-supervised allergy tests may be necessary to confirm an allergy diagnosis.

Negative results indicate that a person probably does not have a “true allergy,” an IgE-mediated response to the specific allergens tested.

Results of allergy blood testing must be interpreted with care. False negatives and false positives can occur. Even if an IgE test is negative, there is still a small chance that a person does have an allergy. Similarly, if the specific IgE test is positive, a person may or may not ever have an actual physical allergic reaction when exposed to that substance.

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How Are Cat Allergies Treated

Cat allergies can usually be controlled with standard allergy drugs. Your doctor might recommend:

  • Antihistamines, which are available over-the-counter like cetirizine , diphenhydramine , fexofenadine , and loratadine or some antihistamines such as azelastine come in a nasal spray
  • , like over-the-counter pseudoephedrine or allergy drugs that contain the ingredient pseudoephedrine such as Allegra-D, Claritin-D, or Zyrtec-D

    Nasal steroid sprays, which affect allergy or asthma symptoms in various ways steroid sprays are a common treatment for allergies. Budesonide , fluticasone , and triamcinolone are steroid sprays that are available over the counter.

Allergy shots are another option. Allergy shots are not always effective, and completing treatment can take years. Theyre also not used for children under age 5. But they can be a huge help to some people. Ask your doctor if they make sense for you.

Unfortunately, theres no way to prevent an allergy. Some studies have shown that exposure to pets as a young child seems to reduce the risk of developing pet allergies later. On the other hand, a child who already has allergic tendencies may get worse with exposure to a pet.

Pros And Cons Of Allergy Blood Tests

Advantages of allergy blood tests include:

  • Can be done at any time, regardless of any medications you are taking
  • Requires only one needle stick this may be more attractive for people who are afraid of needles. Allergy blood testing is the preferred test for infants and very young children.

Disadvantages of allergy blood tests include:

  • More expensive than skin testing many health insurers do not cover allergy blood tests.
  • May be less sensitive than skin tests
  • Takes days or weeks to get results because the blood sample must be sent to a laboratory for evaluation skin testing provides immediate results.

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Allergy Blood Test Vs Skin Test

Allergy blood tests are used to find out if you have an allergy. One type of allergy blood test called a total immunoglobulin E test measures the overall number of immunoglobulin E antibodies in your blood. Another type of allergy blood test called a specific IgE test measures the level of IgE antibodies in response to individual allergens.

In allergy blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

What do the allergy blood test results mean?

If your total immunoglobulin E levels are higher than normal, it likely means you have some kind of allergy. But it does not reveal what you are allergic to. A specific immunoglobulin E test will help identify your particular allergy. If your results indicate an allergy, your health care provider may refer you to an allergy specialist or recommend a treatment plan.

Your treatment plan will depend on the type and severity of your allergy. People at risk for anaphylactic shock, a severe allergic reaction that can cause death, need to take extra care to avoid the allergy-causing substance. They may need to carry an emergency epinephrine treatment with them at all times.

What Happens During The Apt

Comprehensive Food Panel Results explained – Food Allergy Testing Results
  • First, we will use a special tape to place a prepared panel of food extracts on your back.
  • You will be required to keep this panel dry, and in place on your back, for 48 to 72 hours.
  • We will schedule a return appointment in our clinic so your allergist can remove the panel and obtain the test results.

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How Is Allergy Testing Performed On A Blood Test

Radioallergosorbent testing is an outdated form of allergy testing that involves measuring specific allergic antibodies from a blood sample. While RAST is still available, newer forms of blood testing for allergies involves the use of enzyme-linked immunosorbent assays , which involves the binding of allergic antibodies in a blood sample to an allergen, which results in a color change when a developer is added. The darkness of this color change can be measured and translated into a concentration or amount of allergic antibody in the blood sample. While the quality of allergy blood testing has improved in recent years, it is still limited in the number of tests available, as well as the smaller amount of minor allergens present in a particular test .

Allergy blood testing has recently become more useful in the diagnosis and management of food allergies, however. While skin testing to foods can give a sense, based on the size of the reaction, whether a person is truly allergic to the food, allergy blood testing actually measures the amount of allergic antibody to the food. This value can help determine is a child has possibly outgrown the food allergy, for example.

The high cost of allergy blood testing, as opposed to the less expensive skin test, as well as the delay in results of days to weeks, also makes it less desirable than skin testing. Skin testing also continues to be the better test, with less false-positive and false-negative results.

Side Effects Of Allergy Blood Tests

Allergy blood testing is relatively safe. Side effects are usually minor and may include:

  • Swelling and redness at the site where the needle was inserted
  • Pain
  • Bleeding at the site where the needle was inserted

There is a potential that some people may faint during any type of blood testing.

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Summary Of An Allergy Blood Test

An allergy blood test works well for people that are not able to have a skin test done. The skin test is typically the preferred test of allergists as it is less expensive and has a higher chance of being accurate. Some conditions that will decide if a blood test is better is severe skin reactions or medications that you are on. The blood test will show your allergist what substances you are allergic to and from there you both can create an allergy action plan. A blood test is done through a simple blood draw and results are back to you within a few days. In some cases, a false positive occurs which can be a result of an undigested food protein or the test detecting a similar protein. The physician will take the test results, your symptoms, and your medical history into account before diagnosing an allergy.

The Ige Test Explained: Screening For Food Allergies

Allergy Test

Immunoglobulin E is a type of antibody carried by humans and other mammals. It figures prominently in immunity responses and plays a pivotal role in allergic conditions like food allergy and anaphylactic shock. The antibody binds with the antigen. Mast cells then release histamine, and the allergic response occurs.

IgE Levels Read the Number of Antibodies in the Blood

An IgE test measures the blood level of the antibodies, a family of proteins referred to as gamma globulins. Antibodies are important weapons used by the immune system to detect and respond to the invasion of foreign substances like bacteria, viruses, and allergens.

IgE Triggers Allergic Responses

IgE is the primary mediator that stimulates the release of inflammatory agents in mast cells, such as histamine and leukotrienes. IgE also triggers the most devastating of allergic reactions, like anaphylactic shock.

Tests Need to be Interpreted by a Medical Professional

The IgE test may be done to screen for allergies. It is performed by taking a blood sample, which is sent to a lab for testing. The results are processed in a few days. An IgE test will tell you to what degree the body reacts to various types of food or particles and other allergies. A low score does not necessarily mean that a food is safe, but a high score definitely means there is a problem. An unusually low level can actually indicate a rare autoimmune disorder.

Low, Normal and High IgE Levels

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