Are At-Home Allergy Tests Accurate? Here’s What Allergists Say

There's a dizzying array of at-home allergy tests. Find out if the convenience is worth the cost. Here's what allergists say.

Who has an allergy?

At least 50 million Americans have an allergy, be it to food, medications, pollen in the air, cockroaches, or latex. The list goes on—you can even be allergic to reptiles or water—and many types of allergies are on the rise.

The problem can affect not only your skin, but also your respiratory system, eyes, stomach, and in some cases can lead to potentially life-threatening anaphylactic shock.

You may be tempted to find out if you have allergies (and what you’re allergic to) by using an at-home allergy test. However, there are several things you should know before you buy one of these tests. Here’s everything you need to know.

How allergies affect your body

Despite there being so many different types of allergies, they all fall into a handful of categories that tend to have a similar cascade of reactions in your body.

It starts when your immune system misidentifies harmless things (like dust) as foreign and potentially dangerous. Your body produces antibodies, which are immune-system proteins that monitor for threats to your health. The antibodies can trigger the release of chemicals, like histamine, which cause symptoms like itching, rash, wheezing, and more.

Voila, you develop symptoms like hives or sneezing—or worse.

However, keep in mind that when it comes to food, allergies are not the same as food intolerances.

For example, if you have lactose intolerance, you may experience bloating, gas, indigestion and an upset stomach when you consume dairy.

However, a food intolerance is not the same as having a food allergy—it’s more of a problem with digesting a type of food.

A true food allergy—say, to peanuts—tends to be more dangerous than a food intolerance.

Diagnosing allergies at the doctor’s office

There are multiple tests that allergists use to help diagnose allergies, but in order to pick the right test, a doctor needs to find out more about you.

“The tests we do as allergists in our office are based on a person’s exposures, medical history, and medical status,” says Punita Ponda, MD, assistant chief of allergy and immunology at Northwell Health in Great Neck, New York.

This information helps them “pick the right test, for the right patient, for the right diagnosis and make sure that no adverse reaction is likely given the patient’s medical history,” she says.

In other words, allergy tests shouldn’t happen in a vacuum because the tests are nuanced and it’s best to interpret them in the context of actual symptoms and reactions.

Types of allergy tests

Once an initial history is taken, your doctor can select from multiple different tests to help diagnose an allergy. He or she will usually start with a skin test. This involves putting an allergen in contact with your skin, either on the surface or through a small scratch or injection.

If your skin reacts, you may be allergic to that substance. A version of this is the patch test, which means wearing a patch coated with the allergen to see if it provokes a reaction.

Your doctor may also do a focused blood test to look for specific immunoglobulin E (IgE) antibodies.

“IgE is the antibody involved in the allergic response,” says David Stukus, MD, associate professor of pediatrics at Nationwide Children’s Hospital and The Ohio State University College of Medicine in Columbus.

However, just because you’ve created IgE antibodies, it doesn’t mean you will necessarily have symptoms.

People with the antibodies are considered to be sensitized to an allergen, but that doesn’t always translate to swelling, hives, itchy skin, or other symptoms.

Provocation tests—which involve directly exposing you to an allergen—tend to be tests of a last resort. That’s because they need to be done under close medical supervision so any severe reactions can be treated immediately.

(Learn more about three common tests to diagnose a food allergy.)

Young Woman Using Home Blood Test KitOscar Wong/Getty Images

The at-home allergy test

Most at-home allergy tests are blood tests. You drip a little blood on a card provided in the kit and send it off to a lab. Sometimes you have to get the blood drawn at a lab.

It’s not always clear what these tests are measuring, and it may not be the right thing, says Dr. Stukus.

(Read about DIY home tests that could save your life.)

IgE vs. IgG antibody tests

Remember, in order for an allergy test to be useful, it should be administered after considering your medical history (like experiencing symptoms).

When you get an IgE antibody test at the doctor’s office, your allergist will take your medical history into account. This is a valid way to test for allergies.

Some home-based tests measure IgE antibodies. But they may not ask you questions about yourself before they send you a test. Without a clinical history, these tests won’t reveal much because having an IgE antibody doesn’t always translate to symptoms.

“Random IgE testing for multiple allergens as a screening tool is not helpful,” says Dr. Stukus.

Tests that don’t look at IgE are not actually allergy tests.

Some at-home tests measure levels of a different type of antibody, called immunoglobulin G (IgG).

You can develop these antibodies after you’re exposed to various substances, like foods—but it doesn’t necessarily mean you have an allergy.

In fact, because IgG is a “memory’ antibody, it may suggest that you have a tolerance to the food and a healthy immune system should have these antibodies because you’ve eaten that food in the past, according to the American College of Asthma, Allergy, and Immunology (ACAAI).

Therefore, these tests may indicate some type of food sensitivity or intolerance, but it’s not clear they can really determine that.

In some cases, tests may ask you to provide a hair sample, which is not a validated test for allergies.

What are the benefits of at-home allergy tests?

Home-based allergy tests have convenience going for them—but they may not predict actual symptoms or reactions, according to experts.

“These tests do not meet any basic criteria of a good screening test,” says Dr. Stukus. “They cannot be used to find ‘hidden’ allergies and do not predict future reactions.”

(This is what you need to know about at-home Covid-19 testing kits.)

The downsides of DIY testing kits

DIY allergy testing kits can be convenient, but they do come with some downsides. Here are just a few:

The results may be unclear

Often at-home tests come back with a “positive” or “negative” result, which isn’t that useful.

“Allergy tests are not pregnancy tests. They are not simply ‘positive’ or ‘negative,'” warns Dr. Stukus.

Allergy test results should be given as a number, which then needs to be interpreted by a specialist.

They’re not regulated

The Food and Drug Administration (FDA) doesn’t really regulate these tests, so yours may not be FDA approved. (Only a select few are FDA approved.) And some medical groups warn against them.

The American Academy of Asthma, Allergy, and Immunology (AAAAI), for instance, states that the IgG test has “never been scientifically proven to be able to accomplish what it reports to do. The scientific studies that are provided to support the use of this test are often out of date, in non-reputable journals, and many have not even used the IgG test in question.”

They stop short of treatment guidance

Even if they do identify an allergy, at-home tests can’t tell you how to treat it.

They may make eating less fun for you

Relying on the results of at-home tests could lead you to avoid foods or other things that you really don’t need to avoid.

“This can decrease quality of life,” says Dr. Stukus.

Tests aren’t necessarily cheap

Cost ranges from about $25 to several hundred dollars if you get a DIY kit that purports to test for a whole panel of substances.

How to pick a test (if you still want to)

If you still want to try an at-home allergy test, try to make sure you’re using an IgE test.

Because the reliability of home tests is so variable and because the results need to be understood in the proper context, Dr. Ponda suggests speaking to an allergist who can guide the process.

(Learn some surprising triggers of spring allergy symptoms.)

When to contact a doctor

The best way to identify, diagnose, and treat an allergy is to connect with a doctor, preferably an allergist.

Call your doctor “whenever you feel that you can use some help managing them, or even if you’d just like to know what your allergies are,” says Dr. Ponda.

In this day and age, you could start with a telehealth visit (as convenient as a DIY test) to determine if you need follow-up in a clinic or doctor’s office.

Sources

Amanda Gardner
Amanda Gardner is a freelance health reporter whose stories have appeared in cnn.com, health.com, cnn.com, WebMD, HealthDay, Self Magazine, the New York Daily News, Teachers & Writers Magazine, the Foreign Service Journal, AmeriQuests (Vanderbilt University) and others. In 2009, she served as writer-in-residence at the University of Wisconsin School of Medicine and Public Health. She is also a community artist and recipient or partner in five National Endowment for the Arts grants.