Virus Testing 101: Which One Is Right for You?

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—Mobile Health Client
COVID-19 tests



Antibody versus antigen testing? Swab test versus blood test? Short swab versus long?

The array of COVID-19 testing options can be daunting. As a trusted provider of employee health screening services for more than 35 years, Mobile Health can help you navigate the differences.

Antibody vs. Diagnostic Tests

There are two kinds of tests for COVID-19:

  • An antibody test identifies a previous infection and possible immunity.
  • A diagnostic test diagnoses a current infection.  These are also known as molecular or viral tests.  COVID-19 polymerase chain reaction (PCR) tests and Antigen tests are common diagnostic tests.

Let’s take a closer look at antibody testing and the two diagnostic tests.

Antibody Test – Previous Infection

An antibody (IgC) blood test detects COVID-19 antibodies from a previous infection and potential immunity. Depending on its timing, the test may not find antibodies in someone with a current infection. Results are usually returned in one to two days.

Individuals may test positive for antibodies without ever experiencing virus symptoms (asymptomatic).

Antibody tests shouldn’t be used to diagnose a current infection. At this time, it’s unclear if antibodies provide protection (immunity) against getting infected again.

Mobile Health offers antibody IgC testing onsite at client facilities, at four Mobile Health clinics in New York City, and at network locations nationwide. The type of antibody test offered depends on the location.

To learn more, read our Antibody Testing FAQs.

COVID-19 PCR Test – Active Infection

Polymerase chain reaction (PCR) tests (often referred to as COVID-19 tests) are viral swab tests that help diagnose an active infection.  The CDC recommends reserving COVID-19 testing for patients showing symptoms of the virus.

During PCR tests, clinicians use small 1″ swabs (Q-tips) to obtain specimens from the tip of the nose (anterior nares). Longer four-inch swabs collect samples from the back of the nose (nasopharyngeal) or throat (oropharyngeal). Because the shorter swab obtains a smaller sample, it yields more indeterminate or inconclusive results.

Based on current FDA data, PCR tests are highly accurate, but may be time-consuming to conduct and analyze. Results are available in one to three days.

Mobile Health will soon offer COVID-19 testing at our New York City clinics for asymptomatic patients who need clearance to return to work.

Antigen Test  – Active Infection

An antigen test is a viral swab test that can help diagnose an active infection. In May 2020, the FDA authorized antigen testing for use in the ongoing health crisis.

Antigen tests are deployed quickly, with results sometimes provided in minutes. Also, antigen tests generally cost less to produce than PCR tests, with the potential to scale to test millions of individuals per day. It is important to note:

  • They may not detect all active infections, as they are less sensitive than PCR tests.
  • Positive results from antigen tests are highly accurate, but there is a higher chance of false negatives. Negative results from an antigen test may need to be confirmed with a PCR test.
  • Mobile Health does NOT offer antigen testing at this time.

We’re Here to Help

Whether you’re an existing client or new to Mobile Health, we’re ready behind the line to help you incorporate testing into your Return to Work strategy.  That includes screenings to protect frontline workers, like Respirator Fit Tests (RFTs) of N95 masks.

Mobile Health clinics and corporate office will be closed on Monday, May 25th in observance of Memorial Day.