About the Test
Purpose of the test
The purpose of this test is to check the levels of certain antibodies in the blood. These levels are known as antibody titers. When titers are above a certain threshold, it demonstrates that the immune system has had prior exposure to either a vaccine or pathogen.
An antibody titer test can be used in several different situations:
- Assessing past disease exposure: The presence of antibodies can reflect previous exposure to a pathogen.
- Determining vaccination history In people who do not have complete or reliable medical records, an antibody titer test may identify the vaccines that they have already received. Most often, this occurs with children or adults immigrating to the United States without detailed medical records. In this context, it may be referred to as an immunization test.
- Meeting requirements for schools, employers, or assisted-living facilities: Proof of vaccination is required in various contexts, and when medical records cannot provide this proof, an antibody titer test may be an option to prove that you have received a certain vaccine.
- Assessing past disease exposure: The presence of antibodies can reflect previous exposure to a pathogen.
- Evaluating immune function: People with some immune diseases do not properly develop antibodies after pathogen exposure or vaccine administration. This can cause recurring infections or leave them susceptible to vaccine-preventable illnesses. A titer test may be used after vaccination to see if their immune system responds properly.
- Diagnosing autoimmune diseases: In some conditions, the immune system attacks the body’s own cells. The presence of certain types of antibodies can be an indication of an autoimmune problem.
- Protecting healthcare workers: Medical workers may need a titer test to ensure that they have antibodies to viruses to which they have frequent exposure.
What does the test measure?
The test measures antibody titers. This is a technical term for levels of a type of protein produced by the immune system. Specific antibodies are produced in response to specific pathogens like viruses.
The presence of a certain amount of antibodies can demonstrate that a person has been vaccinated or has been exposed to a particular pathogen. A few examples of antibodies in the blood that may be measured to learn about immunization or past infection include:
- Measles and mumps
- Rubella
- Varicella zoster virus, which causes chickenpox and shingles
- Hepatitis A, Hepatitis B
- Tetanus and diphtheria
- COVID-19
Blood can be analyzed to measure dozens of other specific antibodies associated with a broad range of medical conditions. Several different test methods are available depending on the kind of antibodies being measured.
When measuring antibody titers related to immunization, it is important to remember that the presence of antibodies does not guarantee protection. There is no test to definitively prove complete immunity to a pathogen. Also, the absence of specific antibodies does not mean that the body could not mount an immune response against that specific disease. This is because there are other segments of the immune system responsible for fighting pathogens.
When should I get immunization testing?
Antibody titer testing to evaluate immune function or identify active or past infections are tailored to your specific circumstances. Your doctor is in the best position to review the potential benefits and downsides of testing in your situation. Talk with a doctor to determine whether antibody testing is right for you.
In some cases, antibody titer testing may be used to inform a schedule for vaccines. However, when vaccination status is unclear, doctors may recommend age-appropriate vaccinations without doing immunization testing.
Finding an Immunization Test
How to get tested
Antibody titer testing is typically done in specific circumstances when pathogen exposure, vaccination status, or immune system function needs to be checked. As a result, the test is normally prescribed by a doctor who indicates the specific types of antibodies that should be measured.
Can I take the test at home?
At-home antibody titer testing is uncommon. In some circumstances, it may be possible to take a blood sample at home and then send it to a lab where the antibody levels are analyzed.
How much does the test cost?
There is not a standard price for antibody titer testing. Factors affecting the price of the test include:
- Which antibody or antibodies are being measured
- The laboratory techniques used to measure antibodies
- Where you have your blood drawn
- The technician fee for drawing your blood
- Whether you have insurance and whether it provides coverage for the test
- Whether you have cost-sharing like copays or deductibles as part of your insurance
Before getting tested, you can ask your doctor or a representative from a medical lab and your insurance company what the expected cost would be for titer testing for specific antibodies.
Taking the Antibody Titer Test
Antibody titer testing requires a blood sample. The blood sample is normally drawn from a vein in your arm in a doctor’s office, hospital, laboratory, or other health clinic. Some tests can also use blood obtained from a finger prick.
Before the test
You normally do not need to take any special measures to prepare for titer testing. However, you should talk to your doctor about any medications or supplements that you have taken recently as some can affect immune function. You should also tell your doctor if you’ve had any recent illnesses.
During the test
A blood sample for antibody testing is taken from a vein in your arm or from a stick of your finger. If using a vein, the technician will likely tie a tourniquet around the upper part of your arm to enhance blood flow in your arm. They will wipe the area around the inside of your elbow clean with an antiseptic and then use a needle to draw blood from the vein.
There may be a brief stinging sensation when the needle is initially inserted into your arm. This pain usually does not last long, and the test itself can be completed in under one minute.
After the test
Once your blood is drawn, a bandage or cotton swab will be placed over the puncture site to stop the bleeding. It is helpful to hold pressure to the area to help stop the flow of blood. Slight soreness or bruising can occur but normally isn’t long-lasting.
After the test, you can return to most normal activities, including driving. You may need to restrict intense physical activity for a few hours immediately after the test if you are not feeling well after the test.
Immunization Test Results
Receiving test results
Test results are usually available within a few business days after your blood sample is received by the laboratory. If your doctor prescribed the test, they will likely contact you or schedule an appointment to review your results and what they mean. A test report may also be mailed to your home or available to you online.
Interpreting test results
The test result will list any specific antibodies that were measured. It may show a specific level, or titer, measured, or it may simply indicate “positive” or “negative” for whether the antibodies were found.
Interpreting these test results can be complicated because there are different types of antibodies that may be measured. For that reason, antibody test results should be discussed with a doctor who can provide the most relevant context for understanding what they mean and their significance for your health.
