Serum

Red top tube

Preferred Minimum: 1 mL serum
Absolute Minimum: 0.5 mL serum

Grossly hemolyzed, contaminated or heat-inactivated specimens.

24 hours upon receipt at reference laboratory

0.89 IV or less: Negative - No clinically significant level of Toxoplasma gondii IgM antibody detected.

0.90-1.09 IV: Equivocal - Repeat testing in 10-14 days may be helpful.

1.10 IV or greater: Positive - Significant level of Toxoplasma gondii IgM antibody detected and may indicate a current or recent infection. However, low levels of IgM antibodies may occasionally persist for more than 12 months post-infection.

This test is performed using the Siemens Immulite 2000 chemiluminescent immunoassay. As suggested by the CDC, any equivocal or positive Toxoplasma gondii IgM result should be retested using a different assay from another reference laboratory specializing in toxoplasmosis testing, such as Palo Alto Medical Foundation (Remington). The IgG Dye test, IgM ELISA, and reflex to Avidity and/or other tests as indicated should be ordered. In addition, a convalescent specimen should be drawn for comparison. Caution should be exercised in the use of IgM antibody levels in prenatal screening. Any positive results in pregnant patients, that are confirmed positive by a second reference laboratory, should be evaluated by amniocentesis and PCR testing for Toxoplasma gondii.

For male and non-pregnant female patients with equivocal or positive Toxoplasma gondii IgM results, PCR may also be useful if a specimen can be collected from an affected body site.

Acute and convalescent specimens must be labeled as such; parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Please mark specimen plainly as "acute" or "convalescent."

Chemiluminescent Immunoassay

86778

See also:
Toxoplasmosis Antibody, IgG, Serum