The determination of the affinity of specific IgG antibodies against toxoplasma is used to distinguish recent from older parasitic infection in pregnant women, where specific IgM and / or IgA antibodies are not helpful in determining the phase of infection.
Toxoplasmosis is a systemic, parasitic disease caused by the protozoan Toxoplasma gondii. It is transmitted to humans by eating poorly cooked meat from infected animals or ingesting oocysts through the handling of cat litter containing infected feces. It can also be transmitted to the fetus through the placenta by the mother. After ingestion, the parasites travel to various body tissues and cluster together in oocysts.
Acquired toxoplasmosis usually does not cause symptoms in patients with a complete immune system. In cases of immunosuppression, it can cause hyperpyrexia, lymphadenopathy, lymphocytosis and in some cases, encephalitis, pneumonitis, myocarditis, myositis and possibly death. Congenital fetal toxoplasmosis can cause severe abnormalities, including blindness, hydrocephalus, mental retardation, and can lead to endometrial or postnatal death.
Serological testing for Toxoplasma gondii antibody titers is recommended for all pregnant women. If the antibody titer is positive, referring to an infection in the past, there is no risk to the fetus. However, the fetus is at risk if the disease develops during pregnancy. Thus, if the antibody titer is indicative of active infection or is initially negative, the test should be repeated at each microbiological examination in the first 5 months of pregnancy and shortly before delivery. When toxoplasmosis is acquired early in pregnancy, abortion may be suggested. Toxoplasmosis is common in AIDS patients.
Determination of avidity is a diagnostic method used to differentiate recent (acute) from past infection with Toxoplasma gondii in patient serum. Avidity is defined as the binding strength of the antibody (in serum sample) to the corresponding antigen. The low affinity of IgG antibodies in the early stage of infection may be different from the high affinity of antibodies associated with earlier infection. Determination of the affinity of IgG antibodies is an additional analysis in classical serological control in relation to the status of Toxoplasma gondii infection.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. Correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
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