What is Covid-19?
Coronaviruses are a virus family that cause illnesses such as the common cold. In 2019, a new strain of the virus was identified, leading to a new disease that originated in China. This virus is known as severe acute respiratory syndrome coronavirus 2 or SARS-CoV-2 or COVID-19. Unfortunately, in March 2020, the World Health Organization declared the outbreak a pandemic.
How is Covid-19 transmitted?
The exact answer to this question is not clear. Unfortunately, we definitely know that the virus is currently spreading at a high rate. So far, most studies have shown that the virus is transmitted in close contact less than 6 feet (2 meters) between people by respiratory droplets during coughing, sneezing and breathing, talking, and singing.
It has also been found that the virus is spread in some conditions by small particles left in the air, which is called airborne transmission. It should be noted, however, that this is not a common way of transmitting the virus. Contact with contaminated objects or surfaces may also lead to COVID-19 transmission.
People at higher risk from coronavirus
How to prevent covid-19
There is currently no vaccine against COVID-19 on the pharmaceutical market, although successful research is underway to find a vaccine for the disease. Therefore, according to the WHO and CDC recommendations, all people can prevent the spread of COVID-19 by the following:
- Keep a distance of 6 feet with individuals who have symptoms of infection.
- In general, keep a social distance between yourself and other people.
- Wash your hands frequently, or use an alcohol-based hand sanitizer with at least 60% alcohol.
- Use a cloth face mask in public places.
- When coughing or sneezing, cover your mouth and nose, then wash your hands immediately with soap and water.
- Avoid touching your eyes, nose, and mouth.
- Disinfect high-touch surfaces regularly
- Stay home if you are sick.
How to Know you got Infected with COVID-19?
Contact your physician immediately if you have the mentioned symptoms or you have been exposed to the virus. There are currently two tests for this infection:
- A viral test known as PCR (Polymerase Chain Reaction) detects the current infection.
- An antibody test that shows you have had the past infection.
Not everyone needs to do COVID-19 testing. The factors that ascertain whether you need to do a test depend on where you live.
Contact your health care provider first if you have symptoms of the COVID-19 infection and want to do the viral test. He/she will tell you if you need the test and where you can go if you do so. Remember to use a face mask before going to the testing centers.
How to get the COVID-19 viral test?
The lab uses a nasopharyngeal swab to collect a sample of your nose, throat, or saliva. Sampling can be a little uncomfortable. Swabbing may also be done in both nostrils to collect enough samples.
In some cases, your sputum may be sampled for testing. Early in the infection, the virus is more concentrated in the nose and throat, but five days after the onset of symptoms, more virus is found in the lower respiratory tract. Also, because the symptoms of COVID-19 are similar to the flu, your doctor may also consider testing for the flu.
How accurate is a covid antibody test?
Serology testing or antibody testing is often done after full recovery from the COVID-19 disease. Depending on the availability of tests, eligibility might vary. The process begins with the health care worker taking a blood sample, usually from a finger prick or a vein in the arm.
Then the sample will be tested to determine if you’ve developed antibodies or not. The immune system is responsible for producing these critical antibodies/proteins to fight and clear out the virus.
If test results indicate that you have antibodies, it proves that you were likely infected with COVID-19 in the past. It may have meant that you have some immunity as well.
However, there’s no sufficient evidence on the matter that having antibodies means you won’t be reinfected with COVID-19. The level of immunity and the period it will last for is not yet proven. Ongoing studies will reveal more data on this matter at last.
The accuracy depends on the timing and type of antibody test. For example, if you give the test too early or while you are still infected, the immune response will be building up in your body. As a result, the test may not detect antibodies.
That’s why antibody testing is not suggested until a minimum of 14 days after the onset of symptoms. The FDA (Food and Drug Administration) has authorized specific antibody tests; there still may be tests with questionable accuracy.
Another benefit of accurate testing is that recovered people from COVID-19 can donate plasma(a part of their blood). The plasma can be used to treat others with severe illnesses and boost the resistance against the virus.
Types of antibody testing for covid 19
Different types of assays can determine the number of antibodies. The tests are classified to detect binding/neutralizing antibodies. These tests include:
- Binding antibody detection: These tests concentrate on purified proteins of SARS-CoV-2, not live viruses. These tests can be performed in lower biosafety level laboratories. They determine individual antibody types, like IgG, IgM, and IgA.
Both IgM and IgG may be detected at the exact time after infection. However, in comparison, IgM is most helpful for determining recent infections. That’s because it usually becomes undetectable months after the infection.
IgG might remain detectable for more extended periods. IgA is crucial for mucosal immunity and is detected in saliva in addition to blood. Depending on the complexity of tests, some antibody tests are done rapidly (in less than 30 minutes).
Tests that can detect binding antibodies are divided into two broad categories.
- Point-of-care (POC) tests are lateral flow devices to detect IgG and IgM, or general antibodies in fingerstick blood.
- Laboratory tests utilize lateral flow, chemiluminescent immunoassay (CIA), or ELISA for antibody detection in whole blood, serum, plasma, and dried blood spots, which may sometimes require laboratorians and specific instruments. Due to the reagents, total antibody (Ig) is detected, or IgG and IgM are detected separately. Although most tests detect antibodies against S or N proteins, some tests detect antibodies against both immunodominant proteins.
Neutralizing antibody detection tests
These tests can determine the functional antibodies’ ability to prevent infection by virus in vitro. By monitoring inhibition of viral growth in cell culture when it is incubated with serum or plasma. There are three types of this test:
- For virus neutralization tests (VNT), like the microneutralization and plaque-reduction neutralization test (PRNT), they use a SARS-CoV-2 virus from clinical isolates that produce reporter proteins. This testing may take up to five days to accomplish. There are no EUA authorized VNTs yet.
- Pseudovirus neutralization tests (pVNT) that use recombinant pseudoviruses to incorporate the S protein of SARS-CoV-2. These tests can be performed in BSL-2 laboratories. However, it depends on the virus strain used. There are no EUA authorized pVNTs yet.
- Competitive neutralization tests (cVNT) have also been developed. Also, one of them has been approved by the FDA. These are binding tests designed to detect potentially neutralizing antibodies that prevent the interaction of RBD with the ACE-2 receptor. These tests can be done in BSL-2 laboratories as they do not require a live virus.
How long do COVID-19 antibodies stay in your system?
After infection with the COVID-19 virus, the antibodies can take two to three weeks to develop and be shown in an antibody test. So you need to know that you will not be tested too soon. Antibodies may be detected for several months or more after you recover from COVID-19 as well.
What to do after the COVID-19 viral test?
Test results may be prepared within one hour after the test or the same day that you are tested. It may also take several days to prepare the results. COVID-19 diagnostic test results can be positive or negative:
- If the test is positive, you should stay home and quarantine yourself to:
- Improve your symptoms, and at least three days have passed since the last time you had a fever.
- Pass at least ten days after the first sign appeared
If you experience severe symptoms or underlying medical conditions, your doctor may extend your isolation period. If the test is positive, but you have no symptoms, you should stay home for ten days after the test.
- If the test is negative, it indicates that you are probably not infected with the virus. But due to the timing and quality of the test, false-negative results may occur. If the test is negative, you may get an infection in the future. Therefore, you should follow instructions such as social distancing and wearing a mask.
How to get the COVID-19 antibody test?
An antibody test is done on a blood sample to determine if you have had the infection before. This test determines if your body has antibodies against the virus in your body. Antibodies are proteins built by our immune system against microorganisms such as coronavirus.
What to do after the COVID-19 antibody test?
- Positive results: a positive result indicates that you have antibodies against the virus in your body. But these antibodies may be built against other viruses in the coronavirus family. Another key point is that even if you have COVID-19 antibodies in your body, you may still be immune to the virus, but it is not clear how much protection the antibodies may give or how long this protection may last. The CDC has reported cases of reinfection, but remain rare.
- Negative results: If you have not had COVID-19 before, your antibody test will probably be negative.
The body begins to make antibodies within one to three weeks after exposure to the virus. Therefore, your antibody test result may be negative because the body has not yet been able to make enough antibodies. What’s more, some patients never make antibodies against COVID-19 in their body, while others may take longer to produce antibodies.
Differences between PCR and antibody testing
The Importance of COVID-19 antibody testing
Antibodies are proteins that the immune system builds against a microorganism. When your body exposure to a microbe for the first time, the immune system produces antibodies that specifically recognize proteins associated with that particular microbe. Your body needs two to three weeks to make antibodies after getting infected with COVID-19. Therefore, if you do the COVID-19 antibody testing earlier, the results will not be valuable.
Scientists do not know how long the antibody-induced immunity lasts in the body and to what extent past infection protects you from getting another infection. Fortunately, cases of reinfection have been very rare, according to CDC reports. Therefore, it can be said that antibody-induced immunity may remain in the body for a long time. But scientists are still doing more research to understand more aspects of long-term immunity to this strange virus.
CDC currently designed the serologic test for research purposes and surveillance. In this way, they can estimate the percentage of the US population that has already been infected with the virus and protect public health based on the information obtained. In other words, scientists can determine the virus’s spread rate and develop better strategies to deal with it.
When is COVID-19 antibody testing conducted?
The antibody test is recommended in the following cases:
- You have had symptoms of COVID-19 in the past but have not been tested.
- You have had COVID-19 before, and now you want to donate your plasma. This is one of the most important indications of antibody testing. Your blood plasma can help patients with the severe form of infection and is called convalescent plasma therapy.
If you live in Las Vegas and need to take the COVID-19 antibody testing, you can go to the Southern Nevada Occupational Health Center. We advise you to consult your local health department beforehand.
Which antibody tests?
When your body becomes infected with COVID-19, it makes IgM and IgG antibodies at different stages. Total antibody tests help detect both antibodies, but IgG antibody tests only detect IgG, which stays in the body longer and builds long-term immunity.
In COVID-19 infection, the amount of IgM and IgG antibodies increases simultaneously within two to three weeks after the onset of the disease. But it is not apparent how long these antibodies remain detectable after infection. More importantly, it should be noted that not all people develop IgG or IgM following the infection. Therefore, the absence of IgM or IgG antibodies does not mean that a person has not had COVID-19 in the past.
Since the recurrence of COVID-19 is not very common, it may be said that the presence of antibodies reduces the risk of reinfection, but it is not clear for how long and to what extent.
Limitations of Covid-19 antibody testing
The COVID-19 test results may not be very accurate, especially if you immediately take the test after infection. Unfortunately, some manufacturers do not have enough precision and supervision over the production process of antibody test kits. For this reason, you can access online data on the performance of some antibody tests at the US Food and Drug Administration.
In addition to the above, there is a possibility of false-positive or negative results. False-positive results cause you to mistakenly think you are immune to reinfection. However, even with true-positive results, you can not be sure of immunity. False-negative results are also obtained when you do the antibody test soon after infection.
Remember that the body needs time to make antibodies.
Despite a positive test result, you should not be sure that you will not get the infection again. So you still have to wear a mask, wash your hands regularly, and keep your social distance to avoid spreading the virus.
Covid-19 test for travel in Las Vegas
Covid-19 test for the traveler is available in Southern Nevada Occupational Health Centre for travelers and the residents of Las Vegas. You have come to the city and don’t know the area might be looking for a center to complete a COVID-19 test? SNOHC is your trusted option to take the test. Although no COVID-19 test is 100% accurate, we provide the highest level of accuracy with our tests.
The CDC recommends completing a test before flying if you are not vaccinated. Wearing a mask during the flight and staying away from the crowd is also necessary. CDC also recommends keeping the social distance. By the CDC recommendations, you also need to take a test 3-5 days after your flight and stay in quarantine for seven days if your test is negative.
You can take PCR and antibody tests in our occupational health center.
Southern Nevada Occupational Health Center performs antibody and PCR tests in Las Vegas. The SNOHC has been providing Occupational Health services in Las Vegas for plus 15 years. Call us at (702) 381-3989 for further information. To make an appointment, fill the form on the right side out.
Where to get a PCR test near me?
If you need to get a PCR test, you can go to your local or state health department’s website for local test information. We recommend that you contact your doctor before doing the test.
COVID-19 testing in Las Vegas
Southern Nevada Occupational Health Center performs antibody and PCR test in Las Vegas. The SNOHC has been providing Occupational Health Service in Las Vegas for plus 15 years. Now, with the COVID-19 pandemic, we stand by your side. Call us at (702) 381-3989 for further information. To make an appointment, fill the form on the right side out
Frequently Asked Questions about COVID-19 Testing (Antibody test & PCR)
Are you immune to COVID-19 if you get it once?
If you have COVID-19 antibodies, you may be immune, but it is not clear how long this protection may last.
How long does it take to produce antibodies to fight the coronavirus disease?
The body begins to make antibodies within one to three weeks after exposure to the virus.
How dangerous is COVID-19?
Most people have a mild illness, but some, such as the elderly and people with underlying illnesses, may experience more severe symptoms.
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