A titer of 1 to 8 (1:8)
means that antibodies can be found when 1 part of the blood sample is diluted
by up to 8 parts of a saltwater solution (saline). A larger second number means
there are more antibodies in the blood. So a titer of 1 to 128 means there are
more toxoplasmosis antibodies in the blood than a titer of 1 to 32.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range that your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
IgM in babies:
IgM in adults:
Less than 1:64
Less than 1:1024
Toxoplasmosis antibodies usually form within 2 weeks after
being infected. The titer is the highest 1 to 2 months after infection.
- If high titers of the IgM type of antibody are
found, it means the infection is recent. If high titers of the IgG type of
antibody are present, it means an infection occurred in the
- Blood samples may be taken over several weeks to see if the
number of antibodies is getting higher. This would mean the infection is
- Low titers that do not get higher usually mean the
infection occurred in the past. After you have had toxoplasmosis, you cannot be
What Affects the Test
Other infections can cause a
false-positive result in a newborn.
antibodies, such as
rheumatoid factor or antinuclear antibodies, may also
cause a false-positive result.
What To Think About
- If your baby has the IgG antibody, he or she is
not infected. If your baby has the IgM antibody, he or she does have
- Your newborn baby may be given a TORCH test at the
same time as a toxoplasmosis test. TORCH stands for Toxoplasmosis, Other, Rubella, Cytomegalovirus, and
Herpes. The TORCH test checks to see if your baby has
any of these infections.
toxoplasmosis polymerase chain reaction (PCR) test checks your
amniotic fluid to see if toxoplasmosis is present.
This test may be more accurate than other tests in finding an infection in your
growing baby (fetus).
To learn more about toxoplasmosis
infection in pregnancy, see the topic
Toxoplasmosis During Pregnancy.