What this test measures
Toxoplasma IgG measures the long-lived antibody response to Toxoplasma gondii — a single-celled parasite that infects most warm-blooded animals and humans worldwide. Once a person is infected, IgG develops within 1–2 weeks and remains positive for life, signalling past exposure and (in immunocompetent people) lifelong protection from re-infection.
Toxoplasma IgG is one of the four classical TORCH antibodies (Toxoplasma, Rubella, Cytomegalovirus, Herpes) tested before and in early pregnancy. By itself, a positive IgG cannot tell when the infection occurred — IgM, IgG avidity, and clinical history fill in the timing.
Why it matters
Toxoplasma is widespread in India — about 20–30% of Indian adults have IgG evidence of past exposure, mostly acquired from undercooked meat, unwashed vegetables, or contact with cat faeces. In a healthy adult, infection is usually silent or mimics flu. The danger window is pregnancy: a primary infection acquired during pregnancy can cross the placenta and cause congenital toxoplasmosis (hydrocephalus, chorioretinitis, intracranial calcifications, developmental delay).
For Indian women planning pregnancy, the IgG status is genuinely useful information. IgG positive before pregnancy = immune, very low risk of congenital toxoplasmosis. IgG negative before or during pregnancy = susceptible, and care must be taken to avoid raw meat, unwashed produce, and stray-cat litter exposure. In HIV and other immunosuppressed patients, prior toxoplasma exposure (IgG positive) raises the risk of reactivation toxoplasma encephalitis.
How to prepare
No fasting required. Test can be done at any time of day. Mention to your doctor if you eat undercooked meat regularly, handle cats, or are immunosuppressed (HIV, post-transplant, on chemotherapy).
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| Toxoplasma IgG (IU/mL)[1][2] | < assay cut-off = non-immune; ≥ cut-off = past exposure / immune (assay-specific) | Non-immune — no past exposure. In pregnancy, take strict precautions: well-cooked meat, washed vegetables, no contact with cat litter or stray-cat faeces. Re-test if exposure is suspected. | Past exposure / immune. In an immunocompetent person this is reassuring — re-infection is very rare. In pregnancy, an isolated IgG positive (with IgM negative) indicates the infection happened well before conception and no fetal risk is expected. In immunosuppression, reactivation can occur — your doctor will guide monitoring. |
Interpreting Toxo IgG + IgM in pregnancy
| IgG | IgM | Interpretation |
|---|---|---|
| Negative | Negative | Susceptible — take exposure precautions; re-test |
| Positive | Negative | Immune from past infection — reassuring |
| Negative | Positive | Possible very early acute infection — repeat in 2 weeks |
| Positive | Positive | Recent infection possible — IgG avidity test next |
Frequently asked questions
How do people get toxoplasmosis in India?
Most common routes are eating undercooked meat (mutton, pork, chicken), eating unwashed raw vegetables or fruits, and handling cat faeces (litter trays, sandpits) without washing hands. Cats are the only animal in which the parasite completes its life cycle.
I am IgG positive before pregnancy — should I worry?
No. A positive IgG before pregnancy means you are immune from a past infection. Re-infection during pregnancy is extremely rare in immunocompetent people, and your future pregnancies are at very low risk for congenital toxoplasmosis.
I am IgG negative — what precautions should I take in pregnancy?
Eat only well-cooked meat (no rare/medium-rare), wash fruits and vegetables thoroughly, avoid unpasteurised dairy, wear gloves when gardening, and let someone else handle cat litter. Wash hands frequently.
Is toxoplasmosis common in India?
Yes — population studies suggest 20–40% of Indian adults have IgG positivity, with regional variation. Most infections are silent or cause a mild flu-like illness.
Should non-pregnant adults be tested?
Routine testing of healthy non-pregnant adults is not recommended. Testing is done in pre-pregnancy/pregnancy screening, in immunosuppressed patients (HIV, transplant), and in suspected acute infection.
What about my cat?
Pet cats are mostly low-risk, especially indoor cats fed commercial food. Risk comes mainly from cat faeces in contaminated soil. Letting someone else change litter in pregnancy, and washing hands carefully after handling cats, is enough.
How long does the report take?
Most NABL-accredited Mumbai and Thane labs deliver Toxo IgG reports within 24 hours.
Related Infectious Disease tests
Tests commonly ordered alongside TOXO GONDII - IgG, or that help interpret an unexpected result.
Sources & references
- CDC — Toxoplasmosis · accessed 2026-05-30T00:00:00.000Z
- NIH MedlinePlus — Toxoplasmosis Tests · accessed 2026-05-30T00:00:00.000Z
- NCBI StatPearls — Toxoplasmosis · accessed 2026-05-30T00:00:00.000Z
- FOGSI India — Antenatal Screening · accessed 2026-05-30T00:00:00.000Z
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