serology

Are You Positive About that Negative Result?

How to Choose the Right COVID-19 Testing for You.

You may currently have symptoms, or previously experienced symptoms of COVID-19, or you could have been an asymptomatic carrier, either way, it makes sense to get tested to be sure. Keep in mind, however, that not all tests are the same, and that an inaccurate result from an unreliable test can be more dangerous than no result at all.

Don’t get lulled into a false sense of security. Here’s what you need to know to make sure your COVID-19 testing is accurate and reliable, before you jump back into normal life.

Which COVID-19 testing is best for you?

COVID-19 testing falls into two distinct categories. Viral tests, sometimes referred to as diagnostic, molecular or RT-PCR tests, use swabs to check the respiratory cavities for signs of an active infection. This helps determine whether you currently have the virus or not.

Antibody tests, sometimes referred to as serology tests, use blood samples to check for antibodies, which indicate that you’ve experienced a recent or past infection.

Both tests play an essential role in managing the spread of the virus.

If you currently have symptoms or think you may have been exposed to the virus in the last 14 days:

You’ll need viral testing, which requires an oral, nasal, nasopharyngeal swab or a saliva sample. Some tests, known as point of care tests, are analyzed onsite, providing results within an hour. Other diagnostic tests are sent to an offsite laboratory for analysis, which means it can take a few days to get results.

In many cases, sending a test to an outside lab pays off. Analysis by a CLIA-certified laboratory typically generates more reliable results, as the samples are handled by certified labs with advanced equipment and highly trained personnel. Over time, point of care tests will become more accurate. They will also be useful for screening more patients before conducting more invasive and expensive send-out tests.

However, even if you test negative with the most accurate testing, you can still get sick at a later date. Also, if you were tested very early in the course of an infection and tested negative, you could test positive later, once the virus has replicated. For these reasons, it’s important to maintain proper hygiene and social distancing guidelines, no matter what your test result.

If you previously had symptoms or think you may have been exposed more than 14 days ago:

Serology immunoglobulin G (IgG) tests use blood samples to detect antibodies to SARS-CoV-2, the virus that causes COVID-19. Antibodies are proteins that help fight germs within the body. IgG is an antibody that develops later in an infection, typically while you’re recovered. It is specific to the virus, bacteria, or parasite it is targeted against and may circulate for years in your bloodstream.

Since IgG antibodies may take weeks to develop, antibody testing is not particularly effective in detecting an active viral infection. It’s most often used to determine possible immunity, although it’s sometimes used in conjunction with PCR testing to confirm a diagnosis.

If you test positive with a serology test, this means your body has produced antibodies from either a current or past coronavirus infection. Unless you’re currently experiencing symptoms, it’s unlikely you have an active virus. Many immunologists believe that the presence of antibodies to COVID-19 means that you are protected from becoming infected again. However, there is still too little known about how well, how long, or even whether coronavirus antibodies provide total immunity against future infections. Therefore, it’s important that you continue to follow certain precautions until additional information becomes available.

Some people test positive for antibodies without ever having experienced COVID-19 symptoms. This means that you may have had an asymptomatic infection, which is an infection without symptoms.

How are COVID-19 tests evaluated for accuracy?

The CDC, FDA, and other government agencies are working together to evaluate the performance of currently available, commercially manufactured tests. Since extensive government testing can take years, the FDA has authorized emergency use of several diagnostic PCR tests and cleared the way for many serology tests to come to market.

To date, only a few serology tests have received Emergency Use Authorization, or EUA, from the FDA at this point but that does not mean those tests are not accurate. EUA means that a test has attained initial approval after meeting certain base-level criteria. The FDA’s goal with EUA is to speed access to testing, while a more formal and extensive FDA review process is completed.

How to tell a good test from a bad one.

Many tests currently offered have not been cleared by the FDA and are not being offered by reputable moderately or highly-complex CLIA certified labs that can responsibly offer them. In addition, there have been multiple reports of scam operations trying to take advantage of current demand by offering inferior and even dummy tests. Always rely on a provider you know and trust for reliable COVID-19 testing.

As tests become more widely available to a broader group of people, it’s also important to understand differences in testing accuracy. This is why the CDC, FDA, and other government agencies continue to test the tests, as well as the labs, equipment, and personnel that process the test results.

The PCR diagnostic test used by MD Now has been cleared by the FDA under EUA guidelines. The serology antibody test MD Now offers has been submitted to the FDA for clearance under EUA, and is in line awaiting approval. The FDA approves the test’s use by highly-complex laboratories. That is why MD Now has partnered with one of the top CLIA-certified high complexity laboratory companies in the US and uses the “gold standard” in both the PCR and antibody tests. Moreover, all of our testing is completed in Florida ensuring a more rapid turnaround time for your results.

CLIA stands for Clinical Laboratory Improvement Amendments. CLIA labs are overseen by the FDA, the CDC, and the Centers for Medicare and Medicaid Services (CMS).

This means that CLIA-certified labs have met strict federal standards for diagnostic testing, quality, and safety. It’s a notable distinction, given that standards such as these are critical to ensuring accurate assessments of test results at the current rapid pace of processing.

Which test is the right test for you?

Your MD Now provider will determine whether testing is necessary, based on the following criteria:

  • Your signs and symptoms
  • Whether you have been in close contact with someone diagnosed with COVID-19
  • Whether you have previously tested positive for COVID-19 and have not had a subsequent negative test

Serology testing, however, is designed to provide reassurance to those who have already developed antibodies. It also helps researchers determine how COVID-19 is spreading in our communities, and what factors may play a role in how the virus affects certain groups of people.

A positive test for antibodies may not only help determine who might be protected and can safely return to normal life, it can also help identify potential plasma donors. Plasma from those who have successfully fought the virus can be helpful in the treatment of others with more severe illnesses. It may also provide protection against infection until we can develop an approved vaccine.

Consider MD Now Your COVID-19 Testing Headquarters.

MD Now makes COVID-19 testing simple and convenient. PCR diagnostic testing is available by appointment. You can find your nearest location here.

For IgG antibody testing, simply walk in to any South Florida MD Now clinic not designated for diagnostic testing. This extra precaution helps ensure that you get tested for antibodies without putting yourself at risk.

COVID test results are available in 48 hours or less.* We strongly encourage you to check-in for a COVID evaluation, but walk-ins are welcome.

*Result times may vary based on the day and time your test occurs.