Public Health and Environmental Laboratories

Harvest Order Choice: 90211

Synonyms: T. gondii VIDAS TOXO IgG II (txg) Toxoplasmosis Toxoplasma IgG

Program: Virology

Unit: Viral Serology

Useful For: the quantitative detection of IgG antibodies to Toxoplasma gondii in human serum. The VIDAS TXG assay is intended to aid in the determination of immune status of Toxoplasma.

Method: Enzyme-Linked Fluorescent Immunoassay

Charge: N/A

Request Form: SER-1

Container/ Tube: Vacutainer (red, brown or violet top), serum separator tubes

Type: Human serum

Volume: 2-5 ml

Collection Instructions: Venipuncture

Storage: Separated serum should remain at 22 C for no longer than 8 hours. If the assay will not be completed within 8 hours, refrigerate the sample at 2-10 C. If the assay will not be completed within 48 hours, or for shipment of samples, freeze at -25 ± 6C.

Causes for Rejection: Specimens other than serum, specimens with obvious microbial contamination, grossly lipemic, hydrolyzed, or icteric serum.

Interpretation: Samples with less than 4 IU/ml are interpreted as negative

Reference Interval: Negative

Limitations: A negative result does not always exclude the possibility of Toxoplasma infection. Sera collected very early in the acute stage of disease may have IgG levels < 4 IU/ml. Patients with negative results who are suspected of having early disease should be retested in 4-6 weeks. Positive test results from cord blood should be interpreted with caution. The presence of total or IgG anti-T. gondii antibodies in cord blood is usually the result of passive transfer from the mother to the fetus. A negative test, however, may be useful in excluding current infection. Positive test results may not be valid in persons who have received blood transfusions or other blood products within the past several months. VIDAS TOXO IgG II (TXG) results should be used in conjunction with clinical symptoms and other laboratory test results, such as anti-T. gondii IgM results. Test results from immunosuppressed patients may be difficult to interpret, due to diminished immune response. The VIDAS TOXO IgG II (TXG) assay may only be used with serum samples. The use of plasma, amniotic fluid or other body fluids has not been established. The concentrations of anti-Toxoplasma gondii IgG in a given specimen determined with assays from different manufacturers can vary due to differences in assay methods and reagent specificity.

Availability: N/A