COVID-19 Rapid Tests: How Accurate Are They?

Since the start of the COVID-19 pandemic, over 1 billion COVID tests have been performed in the U.S. Early on, it sometimes took days to weeks to get test results. But with fewer roadblocks and improvements in rapid testing, now you can get faster results.

Rapid COVID tests are available at healthcare offices and the shelves of your local pharmacy or supermarket. Here we’ll cover the basics of rapid COVID tests, how fast they are, and the accuracy of the results.  

What is a rapid COVID test?

The key difference between rapid tests and standard laboratory tests is how long they take to process results.

As the name suggests, rapid tests can produce fast results. Compared to standard tests, rapid tests are often simpler. This lets them process samples faster. The fastest test currently available — ID NOW by Abbott — can detect the virus in 13 minutes or less. In general, most rapid tests provide results in 15 to 30 minutes.

You can do rapid tests at point-of-care, like a testing site or a provider’s office. They don’t need an outside laboratory to process. What’s more, many rapid tests are available over the counter (OTC). 

You can also buy these tests without an order or prescription from a provider. And you can get results with these tests from the comfort of your home.

Types of rapid COVID tests

There are two different types of rapid COVID tests available: 

• Molecular tests

• Antigen tests 

These tests work differently in how they detect SARS-CoV-2, the virus that causes COVID. The FDA has also authorized a rapid COVID breath test, but it’s not widely available yet.

COVID-19 (SARS-CoV-2) Antigen Diagnostic Test Kit

Rapid molecular tests

Molecular tests are the most accurate type of COVID tests, rapid or not. Molecular tests detect the presence of viral genetic material in a sample. They were the first type of COVID test to be authorized and widely used. These tests most often use techniques called RT-PCR (reverse-transcription polymerase chain reaction) or isothermal amplification. This means that the test makes thousands of copies of the virus’s DNA found in a sample from your nose. 

Many rapid molecular tests have been authorized for use at point-of-care. These include several that can also test for other viruses, like those that cause the flu (influenza). Most of these tests provide results in 30 minutes or less. 

There are now three FDA-approved, at-home COVID test kits designed to bring PCR-like technology completely into the home: 

• Lucira Check-It COVID-19 Test

• Cue COVID-19 Test

• Metrix by Aptitude 

These tests are more expensive than other types of test kits, but they can be useful. These tests combine the accuracy of PCR testing with the convenience of an at-home antigen test. They deliver results in 30 to 60 minutes.

Your health insurance may cover the cost of rapid molecular tests. If you’re paying out of pocket, the price may vary by provider. Walgreens charges up to $128.99, and Quest charges $125. The Kaiser Family Foundation found that the median price for self-pay (for example, not billing insurance) is $91. But the cost varied widely across the U.S.

Rapid antigen tests

Antigen tests are the most widely available rapid COVID test. Antigen tests look for specific proteins on the surface of the virus. These tests tend to be simpler in design and less expensive than molecular tests. But they’re less accurate than molecular tests (more details on accuracy in the next section).

Many antigen tests have been authorized for use at point-of-care or at home. Several are available OTC, and tests typically take about 15 minutes to get results. 

Your health insurance may cover the costs of these tests. If you have a flexible spending account (FSA), check the eligibility of rapid antigen COVID tests. The median self-pay price for a rapid antigen COVID test at a hospital or outpatient setting is $51. You can also buy them at many locations, including grocery stores and online for less than $10 to over $25 depending on the brand.

How accurate are rapid COVID tests?

Now that you know a little more about how rapid COVID tests work, let’s go over the accuracy of the two types of tests. 

Accuracy of molecular tests

Molecular tests are the gold standard (most accurate option) for COVID testing. Rapid molecular COVID tests use the same technology as the tests in laboratories. Because the test makes thousands of copies of the virus’s DNA if found in the sample, it can detect low levels of virus. If you have a positive result from a rapid molecular COVID test, you’re infected with the COVID virus. 

A negative rapid molecular COVID test means the test did not detect the COVID virus. If you have symptoms, you may still have COVID. But if you test too early, you may not have enough virus to cause a positive result. This is a “false-negative” result. That means you’re infected with the virus, but you’ve tested negative.

If you test negative, it’s also possible you have another infection that causes similar symptoms, like the flu. Either way, it’s important to monitor your symptoms, check in with your healthcare provider, and take basic prevention measures so you don’t spread the virus to anyone else.

Accuracy of antigen tests

Rapid antigen tests are more widely available than molecular tests. Although they’re less accurate, they’re still a good test to understand if you have COVID or not. 

Rapid antigen tests don’t detect low levels of virus. So you may be more likely to get a false-negative result with a rapid antigen test. This is the sensitivity of a test. Because the sensitivity is less than 100%, there’s a chance that you may have COVID even if the test is negative. This is more likely if you test early in the disease, or after you start feeling better. 

Researchers have found that most rapid antigen tests have very high specificity. That means the test has very few false-positive results. With a specificity of nearly or at 100%, if you get a positive result on a rapid antigen test, then you have a COVID infection. This has been the case with Omicron variant infections, too.

Comparing molecular vs. antigen test accuracy

Rapid molecular COVID tests tend to have higher sensitivity and specificity than rapid antigen tests. This is why molecular tests are the gold standard.

Below is a table of some of the sensitivities and specificities of rapid COVID tests.

What causes a false positive on a rapid COVID test?

Rapid COVID tests are very good, nearly perfect, at correctly identifying individuals who have a COVID infection. But you must follow the test instructions to get this high level of accuracy. There have been cases where people received a positive rapid COVID test, but in fact they did not have COVID. These are typically due to user error.

For example, one study found that contaminating the test with commercial drinks like juice and soda can result in a false positive. You can imagine this might happen when testing school children in the lunchroom. Another study found false-positive results due to a manufacturing error in a batch of tests.

How to increase the accuracy of a rapid test

Timing is essential when using rapid COVID tests. You’re more likely to have a false-negative result if you:

• Tested too early (fewer than 5 days after an exposure)

• Have a very mild case, or you’re starting to get better

• Didn’t get a good swab from inside your nose

• Didn’t use the test correctly, or the test was damaged or expired

• Have a variant of the virus that the test doesn’t detect very well

If you’re using at-home rapid antigen tests, it’s recommended that you test multiple times over the course of a few days. For example, if you’re experiencing symptoms but test negative, test again 48 hours later. 

If you’ve been exposed to the virus and don’t have symptoms, wait at least 5 days to test. If you test negative, test again 24 to 48 hours later. If at any point you test positive, you likely have a COVID infection.

Why do people still use rapid antigen COVID tests if they’re not as accurate?

Rapid antigen COVID tests are an easy and quick way to figure out if you have COVID, even if the results aren’t 100% accurate. The number one thing to remember is that if your rapid antigen test is positive, you have a COVID infection. The chances of a false-positive result are very low. And it’s important to take any positive result seriously.

Interpret negative rapid antigen tests with caution. If you have COVID symptoms, test again in 48 hours. If you have been exposed to COVID, take 2 additional tests, each 48 hours apart. If you get a positive result on any repeat test, you have COVID.

Where to find rapid testing near you

If you have COVID symptoms, or believe you’ve been exposed to the virus, you have several options for rapid tests. 

For example, pharmacies like CVS and Walgreens offer rapid antigen and molecular tests. But results may take a few hours. You can also search for other testing locations near you with a search tool from the U.S. government. There shouldn’t be any out-of-pocket costs for testing. But check with your health plan to make sure. 

You can also buy many OTC at-home tests online and at your local pharmacy and grocery store. You can do these tests yourself and get results in an hour or less, depending on the type of rapid test. 

If you have health insurance, your plan should reimburse the cost of eight at-home tests per covered member per month. Make sure to keep your receipts in case you need to submit them for reimbursement.