Toxoplasma Test - IgG

Toxoplasma IgG is a blood test that looks for immunoglobulin G (IgG) antibodies (proteins made by the immune system to fight infection) against Toxoplasma gondii, the parasite that causes toxoplasmosis.

Toxoplasmosis is caused by eating or drinking contaminated food, water, or unpasteurised milk, eating undercooked or raw meat, having blood transfusions or organ transplants, or touching cat faeces. It could also be passed to the developing baby through the placenta during infections in pregnancy, increasing the risk of miscarriage and birth defects. People with weakened immune systems are very likely to get the disease.

Your report may display Toxoplasma IgG test results on its own or as part of a Toxoplasma antibody test with Toxoplasma IgM. Doctors recommend Toxoplasma IgG tests to check for antibodies from past Toxoplasma infections.

A doctor might advise the Toxoplasma IgG test individually or along with Toxoplasma IgM in the following cases:

• When there is suspicion of toxoplasmosis infection.
• In pregnant women, to determine whether they have a current or past infection and whether the baby has been infected.
• HIV/AIDS patients who show symptoms suggesting brain toxoplasmosis, such as headaches, seizures, weakness, speech, or vision problems.
• Individuals with swollen glands without an obvious reason.
• Unusually raised white blood cell counts.
• Inflammation behind the eye.

Healthy individuals need not have regular or repeated Toxoplasma IgG tests. The test is done when the doctor advises it.

The Toxoplasma IgG test can help detect a past toxoplasmosis infection and show whether a person has developed immunity to the parasite. It may be used to assess the following conditions:

• Toxoplasmosis during pregnancy, which can be passed to the unborn baby.
• Toxoplasmosis in a newborn baby, acquired from the mother during pregnancy.
• Brain infections caused by toxoplasmosis, especially in people with weakened immune systems.
• Eye infections caused by toxoplasmosis.
• Toxoplasmosis as a possible cause of swollen lymph nodes.

What to Expect Before the Toxoplasma-IgG Test

No fasting is required for a standalone Toxoplasma-IgG test. You can eat and drink normally. However, if it is part of a broader package that includes fasting tests, your doctor may advise fasting for 8-12 hours. Avoid strenuous exercise for 24 hours before the test, as intense physical activity can temporarily raise Toxoplasma-IgG levels and affect interpretation. Always inform your doctor about any ongoing medications.

What to Expect During the Blood Collection

A phlebotomist cleans the skin with an antiseptic, then places an elastic band around your upper arm to make the veins easier to access. A small needle is inserted into the vein; you may feel a brief pinch. Blood is collected into a labelled tube in under a minute.

What to Expect After the Toxoplasma-IgG Test

A small cotton swab and bandage are placed over the site to stop any minor bleeding. You can return to normal activities immediately. Minor bruising is normal and disappears quickly. If dizzy, sit and rest for a few minutes.

The key parameter in the Toxoplasma IgG test is:

• Detection of IgG antibodies specific to the parasite, Toxoplasma gondii.

The following table shows the Toxoplasma IgG Test normal range.

Note:

• Normal Toxoplasma IgG levels can vary based on age, sex, and the laboratory method used.
• Medical history and symptoms are to be considered along with the test results by the doctor.

The table below provides a general interpretation of IgG test results based on whether the levels are positive or negative.

The Toxoplasma IgG test is generally safe and involves minimal risk. Mild pain, bruising, or slight bleeding may occur at the site of needle insertion. This usually resolves by itself.

Limitations

• An IgG-positive result does not necessarily indicate a new infection, as IgG antibodies can remain in the body for life after infection.
• The test cannot confirm the diagnosis on its own and is usually interpreted together with the Toxoplasma IgM test, other follow-up tests, symptoms, and medical history.
• A negative result does not always rule out infection, especially if the test is done very early, before antibodies have developed. IgG antibodies usually appear within 1–2 weeks of infection.
• Additional tests may be needed, such as repeat antibody testing or other diagnostic tests to confirm the diagnosis, particularly during pregnancy or in people with weakened immune systems.

Depending on your Toxoplasma IgG test results and symptoms, your doctor may recommend additional tests, such as the following, to confirm a diagnosis or identify the underlying cause:

• Toxoplasma IgG test
• Toxoplasma antibody panel (IgG and IgM)
• Amniotic fluid testing
• Brain imaging (CT or MRI)
• Eye examination
• Biopsy of affected tissue