Can you rely on rapid antigen?

COVID-19 is a respiratory disease that can cause serious sickness, particularly in patients who have prior health disorders such as diabetes, obesity, or hypertension. Two different types of rapid antigen tests are frequently performed to determine if a person is currently infected with SARS-CoV-2, the coronavirus that causes COVID-19.

The first sort of test is a polymerase chain reaction (PCR), which is sometimes referred to as a diagnostic or molecular test. A polymerase chain reaction (PCR) test can aid in the diagnosis of COVID-19 by identifying the coronavirus’s genetic material. The Centers for Disease Control and Prevention (CDC) believe PCR testing to be the gold standard for diagnosis.

The second type is a test for rapid antigen tests. These essays aid in the diagnosis of COVID-19 by looking for chemicals on the surface of the SARS-CoV-2 virus.

Rapid antigen tests are COVID-19 tests that offer findings in as little as 15 minutes and do not require laboratory processing. They are frequently in the form of antigen testing.

While fast tests can deliver findings quickly, they are not as reliable as PCR testing performed in a laboratory. Continue reading to learn about the accuracy of quick testing and when they should be used in place of PCR rapid antigen tests.

How reliable are COVID-19 rapid antigen tests?

Rapid COVID-19 rapid antigen tests frequently offer findings within minutes and do not require laboratory analysis by a professional.

The majority of fast tests are rapid antigen tests, and the names are frequently used interchangeably. However, the CDCTrusted Source discontinued the word “quick” when referring to antigen testing, as the FDA has authorized laboratory-based antigen tests as well.

Rapid testing, also known as point-of-care rapid antigen tests, can be conducted in the following settings: 

  • at home using a COVID-19 at-home test 
  • at a doctor’s office • in pharmacies 
  • in school clinics 
  • in long-term care facilities
  • airports 
  • locations for drive-through testing

To collect mucus and cells during the test, you or a medical practitioner will put a cotton swab into your nose, throat, or both. Typically, your sample is transferred to a strip that changes color if you test positive for COVID-19.

While these rapid antigen tests are rapid, they are not as accurate as laboratory testing since they require a higher concentration of virus in your sample to give a positive result. Rapid antigen tests have a significant likelihood of producing a false negative result. learn more about how to perform rapid antigen tests at home at

A false negative result indicates that you do not have COVID-19 when you actually have.

How accurate are self-administered rapid antigen tests?

While at-home testing is not as accurate as gold standard PCR rapid antigen tests, they contribute to the detection of COVID-19 cases that would have gone undiagnosed otherwise. As with other antigen COVID-19 rapid antigen tests, home COVID-19 rapid antigen tests have a greater risk of reporting a false negative than a false positive — that is, it is more probable that the test will say you do not have COVID-19 when you do.

Researchers compared the validity of home antigen testing to PCR laboratory rapid antigen tests for identifying COVID-19 infection in August 2021. Within the first 12 days after symptom onset, home testing accurately identified 78.9 percent of persons who did have the virus and 97.1 percent of people who did not.

When administered within three days of the beginning of symptoms, home testing properly identified 96.2 percent of COVID-19 cases. The researchers discovered that rapid antigen tests performed three days after symptoms began were nearly as reliable as those performed on the day symptoms began.

Probability that a quick test may provide a false negative

A March 2021 analysis of researchers reviewed the findings of 64 trials examining the accuracy of quick antigen or molecular testing commercially available.

The researchers discovered that the rapid antigen tests‘ accuracy varied significantly. Here are their results.

Accuracy for those suffering from COVID-19 symptoms

The rapid antigen tests properly identified persons with COVID-19 symptoms an average of 72% of the time. The 95% confidence intervals ranged from 63.7 to 79%, indicating that the researchers were 95% certain that the average fell between these two numbers.

Accuracy in the absence of COVID-19 symptoms

The researchers discovered that individuals who did not exhibit symptoms of COVID-19 accurately tested positive in 58.1 percent of fast testing. Confidence intervals of 95 percent ranged from 40.2 to 74.1 percent.

Accuracy within the first week following the onset of symptoms vs. the second week

When performed during the first week of symptoms, rapid testing showed a more accurate COVID-19 result. Rapid testing properly detected COVID-19 in an average of 78.3 percent of patients within the first week, the researchers discovered.

Distinction between brands

The researchers discovered a wide variety of test manufacturer accuracies.

Chris Bio concept had the lowest score and properly identified COVID-19 positive patients in just 34.1 percent of instances. SD Biosensor STANDARD Q received the highest score and properly detected 88.1 percent of patients with a positive COVID-19 result.

Researchers assessed the accuracy of four different types of COVID-19 fast antigen testing in another. The researchers discovered that all four rapid antigen tests accurately identified a positive COVID-19 case around half of the time and almost entirely correctly identified a negative COVID-19 case.

Why is it utilized if it is less accurate?

Despite the possibility of receiving a false negative result, fast COVID-19 testing has some advantages over PCR rapid antigen tests.

Rapid examinations:

  • may offer findings in minutes rather than days 
  • are more portable and accessible than lab rapid antigen tests 
  • are less expensive than lab testing

Numerous airports, arenas, theme parks, and other densely populated venues provide fast COVID-19 testing to detect possible positive cases. While rapid testing will not detect every instance of COVID-19, they will detect at least some cases that would have gone undiscovered otherwise.

What should you do if your quick test results are negative but you continue to have symptoms?

If your quick test results indicate that you do not have the coronavirus but do have symptoms consistent with COVID-19, you may have obtained a false negative. It is prudent to confirm your negative result using a more specific PCR test.

How reliable are further COVID-19 rapid antigen tests?

In general, PCR rapid antigen tests are more accurate than fast testing. CT scans are used to diagnose COVID-19 seldom. Antibody testing can be performed to determine the presence of a previous illness. 

PCR assay

COVID-19 PCR testing remains the gold standard for diagnosis. Mucus PCR assays properly detected COVID-19 in 97.2 percent of patients, according to a January 2021 Trusted Source research.

CT scans

CT scans are not routinely used to diagnose COVID-19, although they may help identify the virus if they detect lung issues. They are, however, less useful than other rapid antigen tests and have difficulty excluding other forms of respiratory infections.

The same January 2021 research discovered that CT scans properly identified 91.9 percent of positive COVID-19 cases but only 25.1 percent of negative COVID-19 cases.

Rapid antigen tests for antibodies

Antibody tests seek for antibodies, which are proteins produced by your immune system and indicate previous coronavirus infection. They are specifically looking for antibodies known as IgM and IgG. Antibody testing is ineffective for diagnosing active coronavirus infection.

The January 2021 study discovered that in 84.5 and 91.6 percent of instances, respectively, IgM and IgG antibody testing properly detected the existence of these antibodies.