COVID-19 is a respiratory virus that continues to spread from person to person, but you can protect yourself and others from being infected. Getting vaccinated, tested, and treated can help stop the spread of the virus.
Testing for Covid-19 plays an important role in treatment and helping to reduce the spread. COVID-19 tests are available in medical facilities by healthcare providers and over-the-counter (OTC) for at-home use. By testing at home before you gather with friends or family or when you feel ill, you can determine if you may have COVID-19, so you can take steps to isolate as needed. Walgreens makes it simple to stock up on home tests with a diverse assortment of options.
Antigen at-home COVID tests deliver results in just 15-30 minutes. These tests detect specific proteins found in the virus in the nasal passages, with positive results if COVID-19 is found in the sample and negative results if a certain virus level is not detectable. Typically, antigen tests are most reliable when they produce positive results, especially when symptoms are present. In some cases, it is possible to have a negative test and still be infected, especially if you are asymptomatic. The FDA recommends two negative antigen tests for individuals with symptoms or three antigen tests for those without symptoms, performed 48 hours apart, to ensure you do not have COVID-19. Some at-home kits provide enough supplies for you to perform two tests so that you can easily follow this advice.
You may want to consider getting tested for COVID-19 if you:
When using a COVID-19 test at home, it is essential that you follow the kit instructions carefully, step by step, to get accurate results. Failure to do so can result in inaccurate/invalid results. OTC tests typically require you to use a swab to gather a sample from the inside of your nostrils.
Most tests feature a control indicator. This is a colored band to indicate the test is working properly. There will be a separate line to indicate if the virus was detected. If you don't see the proper control, the test may be faulty or contaminated, so it’s generally best not to use it. Should you receive a positive COVID-19 test result, follow the current guidelines for isolation provided by the CDC or your healthcare provider. You should also contact your healthcare provider for advice about self-care while you recover from the virus.
COVID-19 tests are available for purchase online and in store. Choose a test that is most appropriate for you and make sure that you check the expiration date before using it. If a test was delivered to your home, bring the package inside and leave it unopened at room temperature for at least two hours before opening it. Once the package reaches room temperature, you can administer the test by following the manufacturer’s instructions for use. This helps ensure accuracy of the test results in case there were any temperature changes during shipment.
There are several types of tests that you can take to determine if you are infected or have been infected with COVID-19:
Antigen viral tests: These are the most common type of at-home rapid test, although they’re also available at testing facilities. They can usually provide results in 15-30 minutes. Antigen tests are viral tests that determine whether you have a current COVID-19 infection by detecting part of the virus. Rapid antigen tests are less sensitive than PCR tests, so false negative results are more likely. However, a positive result on an antigen test is very likely to be accurate.
Molecular viral tests: These include nucleic acid amplification tests (NAAT), the most common of which is the PCR (polymerase chain reaction) test. Like antigen tests, COVID-19 molecular tests work by detecting part of the virus. Molecular tests are the most sensitive tests for COVID-19 infection and tend to be more accurate than antigen tests. However, the results can take longer, usually one to two days.
Antibody tests: These detect antibodies, which indicate a past COVID-19 infection. They may also detect antibodies from receiving the vaccine. This test should not be used to determine if you are currently infected with COVID-19.
Some types of home tests are more accurate than others. NAAT tests, such as the PCR, are more accurate than rapid antigen tests and are less likely to yield a false negative result. That means that if your PCR test result is negative, it is very likely that you don't have COVID-19.
Because rapid antigen tests are less sensitive, some people who are infected with COVID-19 may test negative if they don’t have enough viral load for the test to detect. However, a rapid antigen test that comes back positive is a very accurate indication of a COVID-19 infection.
Most rapid tests are rapid antigen tests, and these are less accurate than the PCR tests. There are "rapid" PCR tests that generate results in as little as 30 minutes to a few hours after swabbing, but these tests are done in a doctor's office or lab, not at home.
Rapid antigen tests are more accurate in someone who has symptoms than in someone who doesn't. False positives are unlikely with rapid antigen tests. This means that if you test positive with a rapid antigen test, you most likely have COVID-19. However, if you test negative with a rapid antigen test, you may still be infected, but you may not have a high enough viral load to test positive or infect others.
At-home antigen tests are conducted at home, and they usually provide a result in about 15 minutes. At-home PCR tests are taken at home, but then sent out to a lab, and results usually take days. PCR tests are more sensitive than antigen tests and are typically more accurate. While false positives are unlikely with at-home antigen tests, false negatives are possible.
Rapid antigen tests are less accurate than PCR tests. Rapid antigen tests are more accurate in someone who has symptoms than in someone who doesn't. False positives are unlikely with rapid antigen tests, meaning that if you test positive with a rapid antigen test, you most likely have COVID-19. However, if you test negative with a rapid antigen test, you may still be infected with COVID-19, but you may not have a high enough viral load to test positive.
According to the CDC, if you've been exposed to COVID-19, the best time to get tested is at least five full days after the exposure or if symptoms develop.
Although there is no way to know for sure, the CDC estimates that people infected with COVID-19 are contagious starting two days before symptoms develop until 10 days after symptoms start or 10 days from the date of the positive test if they are asymptomatic.
There's currently no way to know for sure how long you will test positive for COVID-19 after you become infected. A PCR test may be positive for 90 days after you initially test positive, while antigen tests may be negative as soon as five days after initially testing positive. This does not necessarily indicate whether or not you are infectious.
The COVID-19 swab test is not painful, but it may be uncomfortable. There are several ways to collect a specimen:
Nasopharyngeal swab: This is collected by a healthcare professional placing a long swab deep into your nostril to collect fluid from the back of your nose or throat.
Mid-turbinate nasal swab: A healthcare professional (or you, if trained to do so) inserts a swab straight back into the nostril (less than an inch) to collect the sample.
Anterior nasal swab: You or a healthcare professional inserts the swab about 3/4 of an inch into the nostril and twirls it around several times to collect the sample.
Oropharyngeal swab: A healthcare professional inserts a swab into the back of the throat to get a sample.
Saliva: You place spit into a cup to provide a sample.
The nasopharyngeal swab is usually the most uncomfortable, but it provides the most accurate results. Most rapid antigen at-home tests are designed to work with a nasal swab rather than a throat swab.
False-positive results with rapid antigen at-home tests are unlikely. A positive result with one of these tests means it is very likely you have COVID-19.
No, COVID-19 tests are designed to detect the virus, but they do not indicate the specific variant of the virus that is detected. As new variants of the virus develop, it’s possible that the chances of false negative results may increase, according to the FDA.