What is the COVID-19
Antibody (IgG / IgM) Test?
- The first tests made available were invasive nasal swabs that directly detect the presence of the virus. It usually takes 5-7 days to receive results. This is still the best test for patients with signs or symptoms of COVID-19.
- A new test is now available to indirectly detect the virus by measuring the body's COVID-19 antibody levels with turnaround times of 3-5 days.
- Currently, we are only testing for IgG antibody that can indicate past exposure. Testing for Antibody IgM (active infection) will be available in a few weeks.
- It takes at least 10 days after exposure for the IgG to reach detectable levels.
- All test results require interpretation by a medical professional based on your symptoms and history - at this time, in a new area of science, we are cautious in interpreting any COVID-19 test results.
Can antibody tests be used to diagnose active COVID-19 infection or, if positive, tell me whether or not I can be infected again?
Not yet, but hopefully soon. The science is moving quickly.
Is this test perfect?
No, but it is the best option available at this time in our judgment.
Quest Diagnostics (one of the two largest labs in the country) has indicated that the IgG Antibody tests are highly specific and have validated accuracy:
Clinical performance of approximately 90% to 100%
- Specificity of approximately 99% to 100%.
For more information, please visit the Quest Diagnostics FAQ page.
What is the difference between nasal / throat and blood testing?
|Differences||Nasal Swab Test||IgG Blood Draw Test|
Can detect early and onset infection
with most accuracy
Can indicate exposure to COVID-19 if
exposed for at least 10 days
|How does it work?||
Directly detects the presence of
the virus' genetic material
Indirectly detects the virus by measuring
body's immune response (levels of IgM
or IgG antibodies) to the virus
|Sample needed||Nose or throat swab||Blood draw / Venipuncture|
|Time to get results||Typically a week or more||In 3-5 days|
|When should you get it?||
You can get this test if you have
symptoms of COVID-19
You can get this test if you are not showing
symptoms of COVID-19
Who should consider the COVID-19 Antibody Test?
- Anyone over the age of 16 who wants to know if they have had COVID-19 already (either symptomatic or asymptomatic). For example, if you had symptoms prior to testing capabilities or if you know you have been exposed to someone who is or was sick with COVID-19.
- Heatlhcare workers and those who live with healthcare workers
- Other individuals on the front lines including police, fire, EMT and other individuals likely to be exposed
- If you are currently sick and have not yet been tested. Although not a perfect test, this blood test may show if your body has produced the specific IgG antibodies that develop after exposure to COVID-19. However, a negative test results does not mean you don't currently have COVID-19. It could mean that you have not been infected long enough for your body to begin producing antibodies.
Why are you offering this test?
- This test has not been reviewed by the FDA.
- Negative results do not rule out SARS-CoV-2 infection, particularly in those who have been in contact with the virus. Follow-up testing with a molecular diagnostic should be considered to rule out infection in these individuals.
- Results from the antibody testing should not be used as the sole basis to diagnose or exclude SARS-CoV-2 infection or to inform infection status.
- Positive results may be due to past or present infection with non-SARS-CoV-2 coronavirus strains, such as coronavirus HKU1, NL63, OC43, or 229E.
How long does it take to get results?
This test is a blood test and results take about 3-5 days. We will test you and call you with results within a week of your testing appointment.
What do the test results mean?
|Results||What this means||Your actions|
- detection of Antibody IgG
- may suggest exposure to COVID-19 > 10 days ago
- may suggest immune response after
resolution of infection
Additional testing may be required.
Please speak with your doctor.
- Antibody IgG is not present at a level
that is detectable by the test
- rate of IgG development can vary
- DOES NOT rule out COVID-19 infection
Does a positive test mean I am immune?
Although the immune response may protect against reinfection, this has yet to be established.
Does a negative test mean I don't have coronavirus?
Not necessarily. Remember it takes 10 days for this test to turn postive. For more information, please talk to your doctor.
What are IgG and IgM antibodies?
IgM antibodies are the antibodies your body produces during the acute infection stage.
IgG antibodies are the antibodies your body produces during the late stage of infection and remain in your body long after the infection has subsided.
What if I have additional questions about my test?
Please schedule a visit with your primary care doctor.