What is an allergy blood test

Skin and blood tests both own strengths and weakness. Skin tests provide quick results, however, some medicines can affect these tests and the results are sometimes hard to read on darker skin. Blood tests only involve a single needle prick, which is favorite with numerous patients, but it can take a endless time for the results to be returned. These evaluations are not the sole diagnostic tool used by the doctor when investigating potential allergies, but provide supporting evidence to other information gathered during the doctor’s exam.

en españolAnálisis de sangre: inmunoglobulina E (IgE) alérgeno específico

What Happens After an IgE Test?

The health professional will remove the elastic band and the needle and cover the area with cotton or a bandage to stop the bleeding.

Afterward, there may be some mild bruising, which should go away in a few days.

When Are IgE Test Results Ready?

Blood samples are processed by a machine, and it may take a few days for the results to be available. If the test results show signs of a problem, the doctor might order other tests to figure out what the problem is and how to treat it.

What Is an Allergen-Specific Immunoglobulin E Test?

An allergen-specific immunoglobulin E (IgE) test measures the levels of diverse IgE antibodies. Antibodies are made by the immune system to protect the body from bacteria, viruses, and allergens.

IgE antibodies are normally found in little amounts in the blood, but higher amounts can be found when the body overreacts to allergens.

IgE antibodies are diverse depending on what they react to. An allergen-specific IgE test can show what the body is reacting to.

What Is a Blood Test?

A blood test is when a sample of blood is taken from the body to be tested in a lab. Doctors order blood tests to check things such as the levels of glucose, hemoglobin, or white blood cells. This can assist them detect problems love a disease or medical condition. Sometimes, blood tests can assist them see how well an organ (such as the liver or kidneys) is working.

Can I Stay With My Kid During an IgE Test?

Parents generally can stay with their kid during a blood test.

Urge your kid to relax and stay still because tensing muscles can make it harder to draw blood. Your kid might desire to glance away when the needle is inserted and the blood is collected. Assist your kid to relax by taking slow deep breaths or singing a favorite song.

How Endless Does an IgE Test Take?

Most blood tests take just a few minutes.

What is an allergy blood test

Occasionally, it can be hard to discover a vein, so the health professional may need to attempt more than once.

Why Are IgE Tests Done?

An allergen-specific IgE test may be done to glance for some kinds of allergies. These include types of food, animal dander, pollen, mold, medicine, dust mites, latex, or insect venom.

How Should We Prepare for an IgE Test?

Your kid should be capable to eat and drink normally unless also getting other tests that require fasting beforehand. Tell your doctor about any medicines your kid takes because some drugs might affect the test results.

Wearing a T-shirt or short-sleeved shirt for the test can make things easier for your kid, and you also can bring along a toy or book as a distraction.

How Is an IgE Test Done?

Most blood tests take a little quantity of blood from a vein.

To do that, a health professional will:

  1. pull the blood sample into a vial or syringe
  2. insert a needle into a vein (usually in the arm inside of the elbow or on the back of the hand)
  3. clean the skin
  4. put an elastic band (tourniquet) above the area to get the veins to swell with blood
  5. take off the elastic band and remove the needle from the vein

In babies, blood draws are sometimes done as a «heel stick collection.» After cleaning the area, the health professional will prick your baby’s heel with a tiny needle (or lancet) to collect a little sample of blood.

Collecting a sample of blood is only temporarily uncomfortable and can feel love a quick pinprick.

Are There Any Risks From IgE Tests?

An IgE test is a safe procedure with minimal risks.

Some kids might feel faint or lightheaded from the test. A few kids and teens own a strong fear of needles. If your kid is anxious, talk with the doctor before the test about ways to make the procedure easier.

A little bruise or mild soreness around the blood test site is common and can final for a few days. Get medical care for your kid if the discomfort gets worse or lasts longer.

If you own questions about the IgE test, speak with your doctor or the health professional doing the blood draw.

Testing for IgE antibodies may be useful to establish the diagnosis of an allergic disease and to define the allergens responsible for eliciting signs and symptoms.

Testing also may be useful to identify allergens which may be responsible for allergic disease and/or anaphylactic episode, to confirm sensitization to specific allergens prior to beginning immunotherapy, and to investigate the specificity of allergic reactions to insect venom allergens, drugs, or chemical allergens.

Clinical manifestations of immediate hypersensitivity (allergic) diseases are caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE antibodies interact with allergen.

In vitro serum testing for IgE antibodies provides an indication of the immune response to allergen(s) that may be associated with allergic disease.

The allergens chosen for testing often depend upon the age of the patient, history of allergen exposure, season of the year, and clinical manifestations.

In individuals predisposed to develop allergic disease(s), the sequence of sensitization and clinical manifestations proceed as follows: eczema and respiratory disease (rhinitis and bronchospasm) in infants and children less than 5 years due to food sensitivity (milk, egg, soy, and wheat proteins) followed by respiratory disease (rhinitis and asthma) in older children and adults due to sensitivity to inhalant allergens (dust mite, mold, and pollen inhalants).

Detection of IgE antibodies in serum (Class 1 or greater) indicates an increased likelihood of allergic disease as opposed to other etiologies and defines the allergens that may be responsible for eliciting signs and symptoms.

The level of IgE antibodies in serum varies directly with the concentration of IgE antibodies expressed as a class score or kU/L.

Testing for IgE antibodies is not useful in patients previously treated with immunotherapy to determine if residual clinical sensitivity exists, or in patients in whom the medical management does not depend upon identification of allergen specificity.

Some individuals with clinically insignificant sensitivity to allergens may own measurable levels of IgE antibodies in serum, and results must be interpreted in the clinical context.

False-positive results for IgE antibodies may happen in patients with markedly elevated serum IgE (>2,500 kU/L) due to nonspecific binding to allergen solid phases.

Homburger HA: Chapter 53: Allergic diseases.

In Clinical Diagnosis and Management by Laboratory Methods. 21st edition. Edited by RA McPherson, MR Pincus. WB Saunders Company, New York, 2007, Part VI, pp 961-971

What happens during allergy testing?

The first step in an allergy diagnosis is the collection of the patient’s medical history and asking questions to determine if an allergy is the cause of the symptoms. Next, a number of tests will be carried out to test for sensitivities to specific allergens. The doctor may order any number of tests including a skin prick test, blood test, oral food challenge and/or trial elimination diet.

During the skin prick test, the skin is lightly scratched or pierced and a drop of solution containing the allergen will be placed on the patient’s skin to enter the bloodstream.

The tested area is then monitored for a reaction. A blood test involves a sample being drawn to measure the presence of IgE antibodies to known allergens. The presence of these antibodies indicate potential allergies. However, when testing for food allergies specifically, approximately half of blood and skin prick tests can result in a untrue positive. A positive result will indicate to the doctor that an oral food challenge, or an elimination diet, could assist in further diagnoses.

What is an allergy blood test

Special InstructionsLibrary of PDFs including pertinent information and forms related to the test


I recently completed a course of Rhinolight as I suffer from allergic rhinitis, in specific with certain pollen and home dust mites. My symptoms were fairly severe, with sneezing fits, a constantly runny nose and nighttime congestion that hampered my sleep.

Whilst the impact of the treatment wasn’t instantly noticeable (I didn’t own a ‘eureka’ moment), now that the course is over it’s clear that it’s made a massive difference to my day to day existence. I no longer need packets of tissues with me wherever I go, and I am sleeping through the night!

I really wish more people knew about Rhinolight as I genuinely believe it can be a gamechanger for those who suffer from allergies.

What is an allergy blood test


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Dr. Cristina Romete

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    Dr. Nicola Harrison has been the Head of Clinical Governance of ROC London Clinic until 2017 when she was appointed as ROC London Clinic’s Medical Director.

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    What is an allergy blood test

    She graduated from Guy’s and St Thomas’s Medical School, London in 2003. She also became a member of the Royal College of General Practitioners in 2007. She holds the Diploma of the Faculty of Family Planning and the Diploma of the Royal College of Obstetricians and Gynaecology. Dr Nicola Harrison runs our preventative health programmes and childhood immunisation programmes. She consults children and adults for allergy related disorders and she is the clinical lead at ROC for Allergy Assessments and testing.


I recently completed a course of Rhinolight as I suffer from allergic rhinitis, in specific with certain pollen and home dust mites.

My symptoms were fairly severe, with sneezing fits, a constantly runny nose and nighttime congestion that hampered my sleep.

Whilst the impact of the treatment wasn’t instantly noticeable (I didn’t own a ‘eureka’ moment), now that the course is over it’s clear that it’s made a massive difference to my day to day existence. I no longer need packets of tissues with me wherever I go, and I am sleeping through the night!

I really wish more people knew about Rhinolight as I genuinely believe it can be a gamechanger for those who suffer from allergies.


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Gillian Vance

  1. Clinical Interest(s): Food Allergy And Anaphylaxis | Pollen-Fruit Syndrome | Asthma | Allergic Rhino-Conjunctivitis And Immunotherapy | Allergic Gastrointestinal Disease | Urticarial And Angioedema | Drug Allergy | Eczema | Venom Allergy.
  2. Location(s): Aberdeen
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    | MRCPCH (UK) | Dip Med Ed (Newcastle).

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    Dr.Vance qualified in Medicine from Emmanuel College, Cambridge, in 1992. She also took a higher specialist training in Allergy, Immunology and Infectious Diseases at Southampton General Hospital and Grand Ormond Highway Hospital. Dr. Vance has an academic portfolio with initial PhD investigating the early life factors that may influence the development of allergy. She now also leads a team in medical education research at the University of Newcastle.

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    Dr Wassim Fayed is the current Medical Director of ROC London Clinic and he ensures that the ROC London Clinic performs to the level expected of ROC and meets the demands and challenges of modern medicine at an ultimate personal level of healthcare delivery.

What is an allergy blood test?

Allergies are a common and chronic condition that involves the body’s immune system.

What is an allergy blood test

Normally, your immune system works to fight off viruses, bacteria, and other infectious agents. When you own an allergy, your immune system treats a harmless substance, love dust or pollen, as a threat. To fight this perceived threat, your immune system makes antibodies called immunoglobulin E (IgE).

Substances that cause an allergic reaction are called allergens. Besides dust and pollen, other common allergens include animal dander, foods, including nuts and shellfish, and certain medicines, such as penicillin. Allergy symptoms can range from sneezing and a stuffy nose to a life-threatening complication called anaphylactic shock.

Allergy blood tests measure the quantity of IgE antibodies in the blood.

What is an allergy blood test

A little quantity of IgE antibodies is normal. A larger quantity of IgE may mean you own an allergy.

Other names: IgE allergy test, Quantitative IgE, Immunoglobulin E, Entire IgE, Specific IgE

What happens when a person suspects an allergy?

If a patient believes they own had an allergic reaction, he or she will meet with Dr. Rahimi to discuss the symptoms, potential causes, and what testing or treatment is needed.

What is an allergy blood test

The doctor examines the patient and asks detailed questions about the allergic symptoms to understand the situation. He may order a variety of tests to collect more information about the potential allergy. The results of these tests, including the presence of certain proteins in the blood or any rash-like reactions on the skin, would indicate an allergy. Most doctors consent that additional testing and monitoring is necessary to identify food allergies. The doctor may enquire the patient to follow an elimination diet or hold a food diary including details of what has been eaten and any subsequent symptoms.

What is an allergy blood test

Treatment can start once the allergy is identified.