Toxoplasmosis Exposure & Immunity Status Test (IgG & IgM)

Toxoplasma IgM antibodies are produced by your immune system during an active or recent infection with Toxoplasma gondii, a parasite commonly found in cat faeces, contaminated soil, and undercooked meat. These IgM antibodies typically appear within the first week or two of infection and usually decline over several months, though they can occasionally persist longer. What Positive Means: A positive Toxoplasma IgM result indicates recent or current toxoplasma infection. In a pregnant woman, this is a serious finding that requires immediate medical attention, as toxoplasmosis during pregnancy can cause miscarriage, stillbirth, or severe birth defects including brain damage, eye problems, and organ abnormalities. What Negative Means: A negative Toxoplasma IgM result suggests no recent toxoplasma infection. However, if tested very early after exposure, antibodies may not yet have developed. If clinical suspicion remains high, repeat testing may be recommended. Pregnancy and Toxoplasmosis: Toxoplasma infection during pregnancy can be transmitted to the developing baby (congenital toxoplasmosis). The risk and severity depend on when during pregnancy the infection occurs—infection earlier in pregnancy tends to be more severe but less likely to transmit, while later infection transmits more easily but may cause less damage. Early detection allows for antibiotic treatment that may reduce transmission risk. False Positives: Occasionally, IgM tests may produce false-positive results. Positive results are typically confirmed with additional testing, including IgG avidity testing, to determine the timing of infection more precisely.

Toxoplasma IgG antibodies develop a few weeks after infection with Toxoplasma gondii and remain detectable for life, indicating past infection and immunity. Unlike IgM antibodies which signal recent infection, IgG antibodies show that your immune system has encountered the parasite before and has developed lasting protection against it. What Positive Means: A positive Toxoplasma IgG result indicates that you have been infected with Toxoplasma gondii at some point in the past. If IgM is negative, this typically represents old infection and immunity. For women planning pregnancy or who are pregnant, the presence of Toxoplasma IgG without IgM is reassuring—it indicates you're already immune and a new infection won't pose a risk to your baby. What Negative Means: A negative Toxoplasma IgG result means you have no evidence of past toxoplasma infection and are not immune. If you are pregnant or planning pregnancy, you should take precautions to avoid infection: avoid handling cat litter, wear gloves when gardening, wash hands thoroughly after handling raw meat, and ensure all meat is cooked thoroughly. IgG with IgM Positive: The presence of both IgG and IgM antibodies suggests a recent infection. In this case, IgG avidity testing is typically performed to help determine when the infection occurred. Low avidity IgG suggests infection within the past 3–4 months, while high avidity IgG suggests infection occurred more than 4 months ago. Immunocompromised Patients: In individuals with weakened immune systems, past toxoplasma infection (indicated by positive IgG) can reactivate and cause serious illness, including brain abscesses (toxoplasmic encephalitis). Regular monitoring may be recommended for immunocompromised patients with positive IgG.