Rapid virus testing kits are critical in preventing the spread of the coronavirus that causes COVID-19. Rapid testing is so vital to decreasing virus transmission that the National Institutes of Health (NIH) started the Rapid Acceleration of Diagnostics program in April 2020. The program supports the development, production and distribution of accurate, rapid coronavirus testing kits nationwide.
Rapid testing allows employers, healthcare facilities and schools to quickly and easily identify people who have the virus, whether they show symptoms or not, so they can isolate themselves and reduce the chance of infecting others. Early detection of the coronavirus also allows people to get the care they need before the disease progresses, possibly decreasing the severity of COVID-19.
If you’re interested in purchasing rapid COVID-19 testing kits you can use at home or in the workplace and would like more information, you’re in the right place. Below, we cover the basics of current test kits for sale and where you can buy them.
COVID-19 Antigen vs. Antibody Tests
First, it’s essential to know the difference between antibody and antigen tests. Here’s an overview of each:
- Detect an active SARS-CoV-2 infection in the body.
- Look for antigen markers in nasal or throat fluids.
Antigen tests do not tell someone if they had a previous infection and are meant for diagnostic or screening purposes. If someone tests positive on a COVID-19 antigen test, they can isolate themselves immediately, prevent spreading the disease to others and get the help they need.
Your immune system produces antibodies to fight antigens. Antibodies, also called immunoglobulins, are Y-shaped proteins. These proteins bind to antigens and signal other cells in your immune system to eliminate the pathogen. An antibody test can:
- Detect previous SARS-CoV-2 infection.
- Look for antibodies in the blood.
Antibody tests, also called serology tests, are not meant for diagnosing current infections since it takes time for the body to build antibodies. Instead, these tests are usually performed after a person fully recovers from COVID-19.
An antibody test can help people track the spread of the coronavirus. These tests also help scientists determine how many people have been infected with SARS-CoV-2 and possibly have immunity to the virus. But researchers still do not know how long immunity lasts after infection.
At SUNLINE Supply, we sell both types of rapid testing kits.
When Should Someone Take an Antigen Test?
The Food and Drug Administration (FDA) recommends someone take an antigen test if any of the following apply:
- The person has COVID-19 symptoms.
- The individual has had close contact with an infected person.
- The person participated in an activity where they could not maintain social distancing, such as attending a crowded indoor event or gathering.
- A healthcare provider or employer has asked the person to get tested.
Schools, businesses, long-term care facilities and other establishments might have screening programs to test people even if they do not have symptoms or haven’t had a known exposure. A screening program helps keep students, employees, patients, customers and others in a community safe from COVID-19.
When Should Someone Take an Antibody Test?
Although antibody tests do not detect a current infection, they can still be helpful. An expert panel brought together by the Infectious Diseases Society of America (IDSA) identified three reasons for serologic testing:
- When healthcare providers suspect a person has had COVID-19, diagnostic testing is negative and two weeks have passed since symptoms started.
- If doctors suspect multisystem inflammatory syndrome in children, which appears to be linked to COVID-19.
- To conduct surveillance studies.
According to the Mayo Clinic, antibody tests can also be helpful for:
- Patients who have tested positive for COVID-19 in the past and are about to undergo a medical procedure.
- Individuals who have had COVID-19 in the past and want to donate plasma.
Anyone curious as to whether they had COVID-19 might take an antibody test. It’s primarily important antibody tests are not used to diagnose COVID-19 or signify immunity. Even a positive antibody test result does not necessarily mean someone is immune to the coronavirus.
How Do Rapid Covid-19 Tests Work?
Rapid antigen and antibody tests are easy to use and require minimal preparation. Still, these tests involve scientific techniques to provide reliable results. Here’s a little bit about each test type and how it works:
How Antigen Tests for COVID-19 Work
Antigen tests are immunoassays. An immunoassay is a test method that detects specific viral antigens based on their immunological activity. According to the World Health Organization (WHO), most COVID-19 rapid antigen tests use sandwich immunoassays.
A sandwich immunoassay uses two virus-specific antibodies which bind to various sites on the antigen. The “capture” antibody is attached to a solid surface. The antigen and a second antibody, called the detection antibody, are added. The detection antibody and the capture antibody both bind to the antigen. As the number of antigens increases, the number of detection antibodies increases. This activity shows if the virus is present at high levels. Antigen tests for COVID-19 usually use a simple, lateral flow format similar to pregnancy tests.
Some rapid antigen tests are nucleic acid amplification tests (NAATs), though most NAATs need to be processed in a laboratory. NAATs for COVID-19 are high-sensitive molecular tests that detect the virus’s genetic material. NAATs may be used to determine a current or recent infection.
How Antibody Tests for COVID-19 Work
Antibody tests for COVID-19 are assays that also look similar to a pregnancy test. These tests measure a person’s immune response. An antibody test looks for one or two types of antibodies your body creates to fight SARS-CoV-2. These include:
- Immunoglobulin M (IgM) antibodies
- Immunoglobulin G (IgG) antibodies
IgM antibodies form early in an infection, while IgG antibodies appear later and usually stay in the blood once the infection goes away for a certain amount of time.
An antibody test may contain recombinant coronavirus antigen and anti-human IgM and IgG antibodies. When a blood specimen is placed in the sample well, it will bind with the antigen in the cassette if antibodies are present in the blood. As the antigen-antibody complex moves through the test, it will meet the immobilized IgM and IgG antibodies. The complex will react to either antibody or both antibodies, indicating positive results.
How Are Rapid COVID-19 Tests Administered?
Antigen tests examine fluids from the nose and throat — where virus particles are concentrated. Antibody tests, on the other hand, require a blood sample. Here’s a little more about each test and how they are administered:
How Are Antigen Tests Administered?
Since SARS-CoV-2 is a respiratory virus, antigen tests require samples from the nose or throat. Usually, this sample is collected using a swab. Once collected, the specimen is placed in a substance called an extraction buffer. Extraction buffers draw out antigens from the swab sample to enhance the test’s efficiency and accuracy. The specimen is then added to a test device.
To illustrate, here’s an example of how you would administer the Pinnacle Apex COVID-19 rapid antigen test:
- Use a nasopharyngeal swab to collect the sample.
- Add the extraction buffer to the specimen collection tube.
- Insert the swab sample into the collection tube.
- Press the swab against the inner wall of the tube and stir it for about 10 seconds.
- Squeeze the sides of the tube when removing the swab.
- Add the specimen from the collection tube to the test device.
- Set a timer for 15 minutes.
- Read the results after the timer has gone off.
It’s crucial to follow the instructions carefully to ensure the test works correctly. For instance, an antigen test can be affected if it is not stored properly before use.
It’s also worth noting that nasopharyngeal specimens are the recommended swabs, though alternatives may be used. For example, some rapid antigen tests require an oropharyngeal swab, which swabs part of the throat and is considered an acceptable alternative. Overall, antigen tests can be administered in schools, workplaces, healthcare facilities or at home.
How Are Antibody Tests Administered?
Antibody tests for COVID-19 require a blood sample. Rapid tests typically ask users to collect a blood sample by pricking a finger. Here’s an example of an antibody test procedure:
- Clean the puncture site with an alcohol prep pad.
- Push a sterile lancet against the puncture site.
- Draw the blood sample into a pipette.
- Add the blood specimen and buffer into the cartridge’s specimen well.
- Set a timer for 15 minutes.
- Read the results after the timer has gone off.
The test kit you choose should provide all the materials and instructions you need to complete the test. With that said, antibody tests are mostly used by healthcare facilities and laboratories to study the disease and its distribution. The Centers for Disease Control and Prevention (CDC) does not recommend employers use antibody tests to determine if employees should return to work.
How Long Do Rapid COVID-19 Tests Take?
According to the CDC, rapid antigen tests take anywhere from 15 to 30 minutes to get results. Rapid antibody tests may also produce results in 15 minutes. These tests do not need to be sent to labs for processing. Due to their fast turnaround times, rapid COVID-19 tests are appealing options for high-risk settings where it’s vital to prevent transmission.
How Accurate Are COVID-19 Antigen Tests?
Rapid antigen tests are considered accurate when they produce positive results and the instructions were followed carefully. For instance, the Pinnacle Apex COVID-19 antigen test has a 95% confidence interval, representing the test’s accuracy.
Note that an antigen test can produce a false negative result. Antigen tests are most sensitive during the first few symptomatic days or when viral loads are highest. Test sensitivity decreases as the infection progresses and when a person may be less contagious.
If an antigen test shows a negative result but the person has recently been exposed to the coronavirus or has symptoms, their doctor may order a molecular test to confirm the result. Generally, a NAAT is not needed to verify negative antigen test results if a person is asymptomatic and has had no known exposure to the virus. A NAAT also isn’t required to confirm positive test results.
Although NAATs are more sensitive than rapid antigen tests, they also can produce false negative results if viral ribonucleic acid (RNA) levels are too low. Therefore, both tests work best in the early stages of the disease.
How Accurate Are COVID-19 Antibody Tests?
Antibody tests approved by the FDA have high sensitivity and specificity, meaning they produce reliable results. However, since the accuracy of antibody tests can be affected by timing, even the highest quality tests are not 100% accurate.
For example, if an antibody test is taken too early, it may produce a false negative. That’s because it usually takes one to three weeks for a person to develop antibodies after infection. Some individuals never develop antibodies.
With a positive test result, the person likely has antibodies from a SARS-CoV-2 infection. Occasionally, an antibody test indicates a false-positive result. A false positive might occur if the test reads antibodies from a different coronavirus infection.
How Much Do Rapid COVID-19 Test Kits Cost?
In general, rapid COVID-19 testing kits are an affordable alternative to tests that require laboratory processing. According to the CDC, NAATs cost around $100 per test, whereas antigen tests range from about $5 to $50 per test.
Rapid antibody tests cost around $20 per test. At SUNLINE Supply, our antigen and antibody tests range in price from $15 to $32 per test, and we offer pricing tiers with bulk orders.
Where Can I Buy Antigen and Antibody Testing Kits?
You can buy rapid antigen and antibody testing kits online at SUNLINE Supply. We currently offer Pinnacle Apex COVID-19 rapid antigen test kits and Green Spring antigen test kits. The Pinnacle tests are available in boxes of 20 test kits, while the Green Springs tests come in boxes of 25.
We also offer the FaStep IgG/IgM test, an FDA-approved rapid antibody test. This test kit comes in a box of 20.
Buy Bulk COVID-19 Testing Kits Online
Rapid COVID-19 antigen tests are affordable, easy to use and have fast turnaround times. They are key to reducing virus transmission in workplaces, schools, hospitals, households and other high-risk settings. Fortunately, reliable rapid COVID-19 test kits are now available for sale online. If you’re interested in buying rapid antigen or antibody testing kits in bulk, we can help you keep employees, patients or students safe.
SUNLINE Supply is an FDA-certified company carrying only the highest-rated personal protective equipment. We offer 24/7 sales availability and fast shipping speeds, with some products available for immediate shipping. If you would like to learn more about our rapid COVID-19 testing kits or wish to place an order, please contact us today.