Key takeaways:
Diagnosing allergies can be a slow and challenging process. There’s no single test to diagnose allergies, and no test is 100% accurate.
Common tests — like skin-prick testing, immunoglobulin E (IgE) blood tests, patch testing, and allergen challenges — are most helpful when interpreted alongside your symptoms.
A positive test alone doesn’t confirm an allergy — results must be interpreted alongside your symptoms.
Many at-home and alternative allergy tests aren’t backed by science and can be misleading.
Diagnosing allergies isn’t always straightforward. It usually involves a combination of symptom history analysis, a physical exam, and specialized testing. Getting a correct diagnosis can take several months, and the process can be slow, frustrating, and anxiety provoking. Adding to the confusion, many at-home and mail-order tests claim to offer quick and easy results, but most aren’t accurate or scientifically proven to work.
Understanding which allergy tests are accurate can help you avoid unnecessary stress, costs, and delays in getting the right diagnosis and treatment.
What are allergies?
Allergies are an abnormal reaction in the body to an allergen — a generally harmless substance. There are many different types of allergens, including:
Insects
Mold
Pollen
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When someone with an allergy comes across an allergen, their immune system overreacts and tells their cells to release chemicals, causing allergy symptoms (an allergic reaction). Allergy symptoms can happen anywhere in the body, but common places include the:
Allergic reactions differ from person to person. Symptoms can vary. Some people might only have mild symptoms. Other people may have anaphylaxis — a life-threatening reaction. Some examples of common mild symptoms include swelling, sinus pressure, congestion, and skin rash. People may also have itchy eyes, nose, or mouth.
How do allergy tests work?
Allergy tests work by checking to see if your immune system reacts to certain substances (called allergens). There are two main steps to allergy testing:
The first step is that you need to have allergy symptoms when you’re exposed to a specific allergen. For example, your eyes itch around cats.
The second step is to check for a positive result on one (or more) of the allergy tests listed below.
Keep in mind that there’s no single test for allergies, and no one test is 100% accurate. Here are four tests for allergies.
1. Skin-prick test
This is the most commonly used test for allergies. It checks to see if your body has made immunoglobulin E (IgE) antibodies against a specific allergen, like dust mites or a food. A tiny needle injects small amounts of potential allergen into the skin. Then you wait to see if you develop a reaction (a small itchy skin bump at the site of the injection).
How accurate is it?
If you do develop a reaction, it doesn’t necessarily mean that you have an allergy. You can have something called a “false positive” result, which happens about 50% to 60% of the time.
But, if you don’t develop a reaction, that’s a pretty accurate negative result. It means it’s likely you don’t have an allergy to that substance.
2. Blood test
Also called the radioallergosorbent test (RAST), this test looks for IgE antibodies in the blood. It only requires a simple blood draw at any commercial lab.
How accurate is it?
Like the skin-prick test, a positive test doesn’t necessarily mean you have an allergy. A false positive blood test happens about 50% of the time. But a negative test result means you probably don’t have an allergy.
3. Allergen challenge test
This is when you inhale or consume a small amount of an allergen to see if you get allergy symptoms. This is one of the most accurate ways to see if you have an allergy. But it also has a risk of severe side effects (like anaphylaxis). Allergen challenge tests have to take place in a controlled setting with trained healthcare professionals.
How accurate is it?
The false positive rate for allergen challenge tests is very low (around 3%). This means that if you develop a reaction to a specific allergen (like a specific food), you are most likely allergic to it.
4. Atopy patch testing
This is a test you do for a suspected food allergy, when skin-prick and blood tests are negative. Unlike the other tests, this type of allergy test doesn’t involve IgE antibodies. Small patches with different food extracts are taped to your back and left for up to 3 days. A positive result is an itchy skin bump.
How accurate is it?
The accuracy of atopy patch testing depends on what’s being tested. Studies show that it can range anywhere from about 10% to 50%.
How to read allergy test results
Knowing the pattern of your symptoms can help make sense of your allergy test results. For example, if your seasonal allergy symptoms match with a positive test for ragweed pollen, a common cause of hay fever, then there’s a high chance you’re allergic to pollen. But if you have these symptoms and you test positive for a food allergy, that’s less likely to be accurate.
It’s worth remembering that some people may be sensitive to foods but not have a true allergy. A food sensitivity can cause some of the same symptoms as a food allergy. But it’s not caused by an immune system reaction, so your allergy tests will be negative.
How long does an allergy test take?
How long an allergy test takes depends on the type of test. Skin prick tests are usually the fastest, taking about 20 to 30 minutes to see a reaction. A blood test can take a few days to come back from the lab, and atopy patch testing usually takes 72 hours for the final results.
Allergy tests to avoid
Many tests, including at-home allergy tests, claim to help diagnose allergies. Some are available online, by mail order. Others are offered by “special” practitioners. It can be tempting to pay for these tests in the hope of getting quick answers.
But unfortunately, there’s no scientific evidence behind many of these tests. In fact, professional allergy organizations, like the Asthma and Allergy Foundation of America (AAFA), advise people to avoid them. Here are seven allergy tests to avoid.
1. Hair testing
What it is: Hair allergy testing claims to use bioresonance technology to examine hair samples. In theory, certain patterns of electromagnetic resonance from a hair sample can tell you if you have food or environmental allergies.
What science says: There’s no scientific evidence that hair is involved in allergic reactions. Hair may be tested for toxic levels of heavy metals (like too much lead exposure) or nutritional deficiencies (like not enough zinc). But these heavy metals have nothing to do with food or environmental allergies. In summary, hair testing can’t diagnose allergies.
2. IgG food intolerance test
What it is: This test looks for immunoglobulin G (IgG) antibodies in the blood. In theory, the presence of these antibodies can show whether your immune system is sensitive (allergic) to certain foods.
What science says: IgG antibodies are also found in people without food allergies or intolerances. Having these antibodies doesn’t mean you’re sensitive to these foods. It just means your immune system has been exposed to them. Checking for these antibodies can’t accurately diagnose a food allergy or a food intolerance. In other words, a positive IgG food intolerance test doesn’t mean you have a food allergy or intolerance.
3. Vega machine test
What it is: This electroacupuncture machine measures electrical resistance across your skin at various points. These measurements supposedly provide information about food and environmental allergies.
What science says: There’s no scientific evidence that Vega measurements are related to allergies. Results are the same in people who do and don’t have allergies. Experts don’t recommend this test as an accurate way of diagnosing allergies.
4. Applied kinesiology
What it is: In this test, a person holds a suspected allergen in their hands or mouth. A practitioner then assesses muscle weakness. This practice is supposed to figure out whether an allergy is present.
What science says: There’s no scientific evidence that allergies cause muscle weakness. Results may be influenced by the practitioner. It’s not a useful tool for diagnosing allergies.
5. Cytotoxic tests (ALCAT, FACT, and Bryan’s test)
What it is: In this test, a blood sample is mixed with a suspected allergen. The white blood cells are then monitored for injury. In theory, cell injury demonstrates whether or not there’s an allergy.
What science says: There’s no scientific evidence to support this practice. The reaction of white blood cells is unchanged whether or not you have an allergy.
6. Nambudripad’s allergy elimination techniques (NAET)
What it is: This system of diagnosing and treating allergies is based on the belief that allergies are caused by an “energy blockade” and can be treated with acupuncture.
What science says: There are no published studies that say these techniques can accurately identify or treat allergies.
7. Pulse test
What it is: In this test, a practitioner measures your pulse twice, once before you’re exposed to an allergen and then again 15 minutes after exposure. In theory, your pulse will change if you are allergic to the substance.
What science says: There’s no scientific evidence that there’s a reliable connection between increased pulse and allergies.
Why you should avoid unproven allergy tests
Unproven allergy testing can have serious consequences. These tests often cost a lot of money, and health insurance usually doesn’t cover them. Plus, they can lead to false hopes and expectations. They may even delay correct diagnosis and treatment.
Believing you’re allergic to something when you’re not can affect your quality of life — and your health. It may lead you to make unnecessary lifestyle changes, like excluding certain food groups or restricting foods and social situations that you enjoy.
Frequently asked questions
You can get an allergy test through your primary care provider or a specialist, like an allergist. Based on your symptoms, they will recommend the most appropriate type of testing. It’s best to avoid online allergy tests, since they haven’t been proven to work.
The cost of an allergy test varies depending on the type of test and your insurance coverage. For example, one study showed that the average cost of allergy blood testing was lower than skin-prick testing ($161 versus $247). Insurance may cover part of these costs, depending on your plan.
Before getting allergy testing, check with your healthcare team and insurance plan. They can help you understand what’s covered and what you may need to pay out of pocket.
The most accurate allergy test depends on the type of allergy. For environmental allergies (like pollen and dust), skin-prick testing is usually the most accurate and commonly used first step.
For food allergies, an oral food challenge is considered the most accurate test. During this test, a person eats small, gradually increasing amounts of a suspected food to see if a reaction occurs (such as hives or flushing). Because the reactions can be serious, this test is always done in a controlled medical setting.
Consider getting an allergy test if you have ongoing or repeated symptoms that don’t go away. Allergies can look different for everyone, so your symptoms may not be the same as someone else’s. Common signs to watch for include:
Stuffy nose
Watery eyes
Chronic cough
Itchy skin or rashes
Hives, lip itching or swelling, or coughing and trouble breathing after eating certain foods
If you’re not sure whether your symptoms are related to allergies, talk with a healthcare professional. They can help you decide if testing makes sense.
You can get an allergy test through your primary care provider or a specialist, like an allergist. Based on your symptoms, they will recommend the most appropriate type of testing. It’s best to avoid online allergy tests, since they haven’t been proven to work.
The cost of an allergy test varies depending on the type of test and your insurance coverage. For example, one study showed that the average cost of allergy blood testing was lower than skin-prick testing ($161 versus $247). Insurance may cover part of these costs, depending on your plan.
Before getting allergy testing, check with your healthcare team and insurance plan. They can help you understand what’s covered and what you may need to pay out of pocket.
The most accurate allergy test depends on the type of allergy. For environmental allergies (like pollen and dust), skin-prick testing is usually the most accurate and commonly used first step.
For food allergies, an oral food challenge is considered the most accurate test. During this test, a person eats small, gradually increasing amounts of a suspected food to see if a reaction occurs (such as hives or flushing). Because the reactions can be serious, this test is always done in a controlled medical setting.
Consider getting an allergy test if you have ongoing or repeated symptoms that don’t go away. Allergies can look different for everyone, so your symptoms may not be the same as someone else’s. Common signs to watch for include:
Stuffy nose
Watery eyes
Chronic cough
Itchy skin or rashes
Hives, lip itching or swelling, or coughing and trouble breathing after eating certain foods
If you’re not sure whether your symptoms are related to allergies, talk with a healthcare professional. They can help you decide if testing makes sense.
The bottom line
Diagnosing allergies takes time, patience, and the right approach. A reliable diagnosis is based both on your symptoms, physical exam, and specialized testing, like skin-prick tests and blood tests.
Other types of at-home allergy tests and consultations promise to provide answers. But hair testing, Vega machines, IgG tests, and kinesiology don’t work. Beyond the high cost, they can lead to false hopes for a cure, extreme exclusion diets, and stress. They can also delay the correct diagnosis and treatment.
If you think you may have allergies, it’s best to get guidance from a trained healthcare professional.
Why trust our experts?
References
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University of British Columbia. (2019). “Gold standard” food allergy test faces implementation barriers, but solutions possible.
Vaidyanathan, V., et al. (2019). Atopy patch test. Indian Journal of Dermatology, Venereology and Leprology.
