ARUP's Laboratory Test Directory

Toxoplasma gondii Antibody, IgM : 0050557

Mnemonic: TOXEIGM

Methodology: Chemiluminescent Immunoassay
Performed: Sun-Sat
Reported: Within 24 hours
Specimen Required: Collect: Serum separator tube. Also acceptable: Serum from umbilical cord blood.

Specimen Preparation: Allow specimen to clot completely at room temperature. Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Mark specimen plainly as "acute" or "convalescent."

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Urine. Contaminated, heat-inactivated, or grossly hemolyzed specimens.

Stability (collection to initiation of testing): After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
Reference Interval:
 
7.9 AU/mL or less: Not Detected.
8.0-9.9 AU/mL: Indeterminate - Repeat testing in 10-14 days may be helpful.
10.0 AU/mL or greater: Detected - 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.

Interpretive Data: This test is performed using the DiaSorin LIAISON. As suggested by the CDC, any indeterminate or detected Toxoplasma gondii IgM result should be retested in parallel with a specimen collected 1-3 weeks later. Further confirmation may be necessary using a different test from another reference laboratory specializing in toxoplasmosis testing where an IgM ELISA should be ordered. Caution should be exercised in the use of IgM antibody levels in prenatal screening. Any Toxoplasma gondii IgM in pregnant patients that have also been confirmed by a second reference laboratory should be evaluated by amniocentesis and PCR testing for Toxoplasma gondii.

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

For additional information, refer to the CDC website: www.cdc.gov/parasites/toxoplasmosis/health_professionals/index.html.
CPT Code(s): 86778
Cross References: Toxoplasma IgM, ELISA, Serum (Toxoplasma gondii Antibody, IgM)