Immunoglobulin G antibodies, immunoglobulin M antibodies, Sabin-Feldman dye test, ELISA, IFA test, agglutination test
This test looks for antibodies against Toxoplasma gondii (T. gondii) infection in your blood.
T. gondii is a parasite that can infect people when they:
Eat infected meat, especially lamb or pork, that hasn't been thoroughly cooked
Drink contaminated water
Swallow the parasite after being exposed to it while cleaning a cat's litter box
(Cats can become infected after eating animals carrying the parasite and shed the parasite in their feces.)
In healthy adults, infections often don't cause any symptoms. But in people whose immune system isn't working properly, a T. gondii infection can cause brain damage and other serious complications. When pregnant women become infected, it can cause stillbirth, severe birth defects, or complications that can be seen in the child years later.
You may need this test if your doctor suspects that you have toxoplasmosis. Most people who become infected with T. gondii aren't aware of it. Symptoms of the infection vary and include:
Flulike symptoms, such as achiness and swollen lymph nodes
Blurry vision, eye redness, and pain if the disease is affecting the eyes
A small number of infected infants have brain or eye damage at birth.
If you're pregnant, you may also have this test, especially if you may have been exposed to T. gondii.
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.
Test results can show whether you have higher levels of immunoglobulin G (IgG) or immunoglobulin M (IgM) antibodies – or sometimes immunoglobulins A and E – that are related to T. gondii infection. IgM antibodies tend to show up faster and subside faster after an infection. IgG antibodies tend to slowly fall over the next year or two.
The results can tell your doctor whether you have a new, acute infection or had an infection in the past.
If you have AIDS and toxoplasmosis, you may have a relatively small elevation in IgG, and the results for IgM and other antibodies against the parasite may show up negative.
The test requires a blood sample, which is drawn through a needle from a vein in your arm.
Other factors aren't likely to affect your results.
Tell your health care provider if you have a condition that affects your immune system or are taking any medicines that may do so. It's best to be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.