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Test Code TOX IGG/TOX IGM Toxoplasma Antibodies, IgG and IgM, Serum

Infectious

Additional Codes

Supplemental Test Code
5202

Methodology

Multiplex Flow Immunoassay, Bio-Rad Bioplex 2200 

Testing Algorithm:

If Toxoplasma IgM is positive, confirmation will be performed, at an additional charge.

Literature References:

1. Package insert: Bio-Rad Bioplex 2200 System ToRC IgG IFU. 04-2019

2. Package insert: Bio-Rad BioPlex 2200 System TRC IgM IFU. 08-2017
 

Performing Laboratory

Barnes-Jewish Hospital Laboratory

Specimen Requirements

Specimen Type: Serum
Container/Tube: Plain red top, Red/Grey SST or Gold SST
Specimen Volume: Full tube
 

Specimen Transport Temperature

Ambient

Reference Values

Reference Value

Toxoplasma, IgG - Negative

Toxoplasma, IgM - Negative
 

Literature References:

1. Package insert: Bio-Rad Bioplex 2200 System ToRC IgG IFU.04-2019

2. Package insert: Bio-Rad BioPlex 2200 System TRC IgM IFU.08-2017

3. Clinical Laboratory Standards Institute(CLSI).  Clinical Use and Interpretation of Serologic Testing for Toxoplasma gondii, Approved guideline.  (M36-A), Feb 2004

Day(s) Test Set Up

Monday through Sunday, 0700 - 1300
Turnaround Time:
STAT: not available
Routine: results available the day of testing.

Test Classification and CPT Coding

86777-Toxoplasma IgG

86778-Toxoplasma IgM

86778-Toxoplasma IgM confirmation (if appropriate)

Additional Information

For BJH Laboratory Use Only

Analyte Stability:

Specimen stored at room temperature(18-30° C) for 3 days and store specimen at 2-8° C up to 7 days. Freeze specimen, devoid of RBCs, at ≤-20° C for longer storage. Do not store in frost-free freezers. Specimens tested after 3 freeze/thaw cycles showed no qualitative differences. Mix thoroughly after each thawing.

Avoid hemolysis.

Laboratory Processing Instructions:

Test performed in BJH Core Lab. Centrifuge, separate serum, and refrigerate at 4° C for 7 days.

LOINC Code Information

Name LOINC Code
Toxoplasma Antibody, IgG 5390-0
Toxoplasma Antibody, IgM 5335-5

 

Interpretive Data

Toxoplasma, igG

Negative- No detectable antibody.
Equivocal - Presence of detectable antibody cannot be determined.
Positive - Detectable levels of antibody present.

Toxoplasma, IgM 

A positive result for Toxoplasma IgM must be interpreted cautiously, and in the context of clinical findings. Due to a high rate of false positive results with this assay, Clinical Laboratory Standards Institute (CLSI) guidelines recommend confirmatory testing with a different assay at a reference laboratory ( Clinical Laboratory Standards Institute(CLSI).  Clinical Use and Interpretation of Serologic Testing for Toxoplasma gondii, Approved guideline.  (M36-A), Feb 2004).  Therefore, all initial positive results for Toxoplasma-specific IgM will be sent to Palo Alto Toxoplasma Serology Laboratory  for confirmatory Toxoplasma-specific IgM testing.  Results will be reported separately in a scanned report

Notes:

1. In patients infected with Toxoplasma gondii, the IgM antibody appears immediately before, or soon after, the onset of symptoms.

2. The U.S. Food and Drug Administration has advised that no one commercial Toxoplasma IgM test should be used to determine acute infection. If Toxoplasma IgM is positive, confirmation will be performed, at an additional charge. 

3. Levels of IgG antibody to Toxoplasma gondii begin to rise 1 to 2 weeks after infection. Peak levels are reached in 6 to 8 weeks, then gradually decline over months to years. Low titers are generally detectable for life. The antibody titer does not correlate with severity of illness.