Antibody Testing

What you need to know about antibody testing.

What is an antibody?

Our immune system creates antibodies in response to infections. It’s our body’s way of fighting off intruders and keeping us safe. Some antibodies develop naturally and last a lifetime. Others are given to us by vaccination. Those who had chicken pox as children have antibodies, which is why we only get chicken pox once. Younger people received the vaccine when it was made. They, too, have antibodies protecting them.

What about the COVID-19 antibody?

People who have been ill with COVID-19, like with other viruses, will almost always develop antibodies, which are detectable in the blood about 14 days after becoming ill. What’s different about COVID-19 is it’s a new virus, so we can’t be sure about what having antibodies means in this case. It should mean we have immunity and they should last, but since this is an unprecedented situation, we can’t be certain. Our direction to our own medical and support staff at Englewood Health is that having antibodies will not change the work they do, nor the need for personal protective equipment. Until we know different, we must chart the safest course.

What if I was sick and my antibody test is negative?

No test is perfect. The ability of a test to read positive when it should is referred to as its sensitivity, but no test is 100% sensitive—there’s always a chance the test may show a false negative. The other reason a test may read negative is that, for some reason, insufficient antibodies were created, which sometimes happens.

What if I was not ill and my test is positive?

It likely means you were exposed to the virus and had few, if any, symptoms. Your immune system jumped in, though, and protected you with antibodies.

How can I be tested?

All primary care offices in the Englewood Health Physician Network can perform the COVID-19 antibody test. In addition, our urgent care office in Cresskill will perform the test for any patient, following a brief discussion. The test must be run in a lab, so results are available within 1–2 days. Englewood Health Urgent Care It is open seven days a week. No appointment is necessary. Call 201-205-2172 to learn more.


If you think you currently have COVID-19, please call your primary care physician. If you need help finding a physician, please call 1-833-234-2234.

To learn more about COVID-19 antibody testing, please visit the CDC’s website.