Antibody Serology Tests Test
An antibody serology test checks your blood for antibodies—proteins your immune system makes to fight germs. It can show if you have had a past infection or a vaccine, but it cannot tell if you are fully protected or how long protection lasts.
What this test measures
Antibody serology tests look for specific antibodies in your blood. Antibodies are proteins your immune system makes to fight disease-causing germs, such as viruses and bacteria. The test can measure endogenous antibodies (made by your body after infection or vaccination) or monoclonal antibodies (artificial antibodies used in certain treatments).
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
If antibodies to a specific pathogen were found, it may mean you had an infection before or you've been vaccinated against that disease.
Lower-than-normal results
Low levels of certain antibodies may mean an earlier vaccination does not provide enough protection, and you may need a booster shot.
Frequently asked questions
What are antibody serology tests used for?
They are used to see if you have antibodies from a past infection or vaccination, to check for signs of autoimmune disease, or to see if you need a booster shot.
Can an antibody test tell if I have a current infection?
No. The test looks at your body's response to a pathogen and cannot show if the antibodies are from a current or past infection or from a vaccination.
How long does it take for antibodies to appear after infection or vaccination?
It may take a few weeks for your body to make antibodies after you have had an infection, been exposed to a pathogen, or had a vaccine.
What do positive results mean?
Positive results mean antibodies to a specific pathogen were found. This could mean you had an infection before or you have been vaccinated against that disease.
What do low antibody levels mean?
Low levels of certain antibodies may mean an earlier vaccination does not provide enough protection, and you may need a booster shot.
Related lab tests
Sources
- MedlinePlus: Antibody Serology Tests — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.