There is much information in the news about the newly released Covid-19 antibody tests. What do these tests look for and how accurate are they?
What are antibodies?
When you contract an infection, such as Covid-19, your body produces antibodies to fight that infection. These antibodies are produced immediately but their level rises in your blood as your body produces more antibodies to fight the infection. Each person produces antibodies at different rates and the level of antibodies in your blood can therefore vary. The higher your antibody level is, the more active your immune system has been in fighting off the infection. With most infections the higher your antibody level is the more your body is protected from being re-infected with that disease.
What does the current antibody test measure?
The current antibody tests looks for the level of antibodies against Covid-19 which we assume will protect you from re-infection. Most individuals do not produce enough antibodies to be detected in the blood until 7-10 days after they have been infected. In some individuals antibody levels may not be high enough to be measured until 6 weeks after they have been infected. The current antibody test available is a blood tests and we use commercially available labs which have a high rate of accuracy.
What do the results of antibody testing show us?
When we receive results from antibody testing we need, as physicians, to interpret those results. If your test is negative you may not have been exposed to Covid-19 or it is too early after exposure to the illness and you may not have produced enough antibodies to be detected by the test. If your test is positive then you were exposed and have developed antibodies to the illness.
If you do have antibodies what does that mean for your long-term risk of being re-infected? As physicians we just do not know now if higher antibody levels will protect us from Covid-19 re-infection, but our past experience has shown us that those with antibodies to an illness have a much lower chance of re-infection than those with no antibodies. Your overall health status will also determine your future risk.
Please call my office to arrange for antibody testing and follow-up. I am here to help you navigate the uncertain times ahead and I promise to keep you and your family as healthy as possible.
