Ordering Recommendation

First-line test for identifying visceral T. gondii infection. CDC suggests equivocal or positive results should be retested using a different assay from another reference laboratory specializing in toxoplasmosis testing (IgG dye test, IgM ELISA, reflex to avidity and/or other tests).

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation
Collect

Serum Separator Tube (SST).

Specimen Preparation

Allow specimen to clot completely at room temperature. Separate from cells ASAP or within 2 hours of collection. Transfer 2 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.

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Plasma or urine. Contaminated, heat-inactivated or grossly hemolyzed specimens.

Remarks

Label specimens plainly as "acute" or "convalescent."

Stability

After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)

Methodology

Semi-Quantitative Chemiluminescent Immunoassay

Performed

Sun-Sat

Reported

Within 24 hours

Reference Interval

Test Number
Components
Reference Interval
  Toxoplasma gondii Ab, IgM 7.9 AU/mL or less

Interpretive Data




Component Interpretation
Toxoplasma gondii Antibody, IgG 7.1 IU/mL or less: Not Detected.
7.2-8.7 IU/mL: Indeterminate - Repeat testing in 10-14 days may be helpful.
8.8 IU/mL or greater: Detected.
Toxoplasma gondii Antibody, IgM 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.

Compliance Category

FDA

Note

This test should not be used for blood donor screening, associated re-entry protocols, or for screening Human Cell, Tissues and Cellular and Tissue-Based Products (HCT/P).

Hotline History

N/A

CPT Codes

86777; 86778

Components

Component Test Code* Component Chart Name LOINC
0050557 Toxoplasma gondii Ab, IgM 8040-8
0050770 Toxoplasma gondii Ab, IgG 8039-0
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • Torch
  • Torch IgG
  • Torch IgM
  • Toxoplasma gondii Ab, IgG
  • Toxoplasma gondii Ab, IgM
Toxoplasma gondii Antibodies, IgG and IgM