Finding the right tests…
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Finding the right tests…
ELISA
Toxoplasma IgM appears in your blood when your immune system is responding to a new or recent infection with Toxoplasma gondii, and unlike IgG, it doesn't mean lasting protection - it's a signal that infection happened recently, possibly within the current pregnancy if you're pregnant. This matters because a first-time Toxoplasma infection during pregnancy, not an old one, is what can pass to the baby and cause serious problems including damage to the brain and eyes. A positive IgM result on its own isn't the final word - it's usually followed by more specific testing to confirm timing before anyone makes decisions based on it.
A positive IgM result raises the question of a recent infection, but this antibody can occasionally stay detectable for many months after the infection actually happened, sometimes long enough to create confusion about timing, especially in pregnancy where timing changes everything. Because of this, a positive IgM result - particularly in a pregnant woman - is usually followed by an IgG avidity test, and sometimes referral to a specialist reference laboratory, rather than treated as confirmation of a brand-new infection by itself.
For most infections, finding IgM just confirms something recent happened. With Toxoplasma, the stakes are higher during pregnancy specifically, because an infection before conception is essentially harmless to the baby, while one during pregnancy can cause serious congenital problems - so working out exactly when an IgM-positive result reflects infection matters enormously.
This antibody can linger for many months in some people, well past when it's still telling you something new happened. A positive IgM result taken alone can be misleading about timing, which is why doctors typically add an IgG avidity test, and for pregnant women with an unclear result, refer to a specialist laboratory for confirmatory testing.
- An IgG avidity test is done to estimate how long ago the infection happened - If the timing is unclear or points to a recent infection, closer monitoring of the pregnancy follows - Specific antibiotic treatment can reduce the chance of the infection passing to the baby
It's not a general screening test for people without symptoms or pregnancy-related risk, and a positive result in someone with no relevant exposure is interpreted far more cautiously than one with a clear clinical reason for testing.
It suggests a recent or current infection, but this antibody can occasionally stay detectable for many months, so timing isn't always clear from IgM alone. Your doctor usually follows up with an IgG avidity test to narrow down when the infection actually happened.
An infection that happened before conception generally doesn't harm the baby, but one that happens during pregnancy can, so knowing whether a positive result reflects an old or new infection changes how the pregnancy is managed. This is why extra tests often follow a positive IgM result.
Yes, IgM can occasionally remain positive for many months after the actual infection, which is why it's not treated as proof of a brand-new infection on its own, especially in pregnancy.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
Your doctor typically orders an IgG avidity test and monitors the pregnancy more closely while the timing is worked out. If a recent infection is confirmed, specific antibiotic treatment can reduce the chance it passes to the baby.
There's no fasting requirement for this test. Ask your doctor or the centre when you book, especially if it's part of a wider antenatal panel.
It's generally not recommended as a routine check without symptoms or a specific reason like pregnancy or a weakened immune system, since interpreting a positive result without that context is harder. Ask your doctor whether testing makes sense for your situation.