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Test Code TXPAB Toxoplasma gondii Antibody, IgM and IgG, Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.7 mL

Collection Instructions: Centrifuge and aliquot serum into plastic vial.


Secondary ID

621836

Useful For

Qualitative detection of IgM and quantitative detection of IgG antibodies to Toxoplasma gondii in human serum

Profile Information

Test ID Reporting Name Available Separately Always Performed
TXPM Toxoplasma Ab, IgM, S Yes Yes
TXPG Toxoplasma Ab, IgG, S Yes Yes

Testing Algorithm

For more information see Meningitis/Encephalitis Panel Algorithm.

Method Name

Electrochemiluminescence Immunoassay (ECLIA)

Specimen Type

Serum

Specimen Minimum Volume

0.7 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 21 days
  Frozen  90 days
  Ambient  72 hours

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject
Additives (eg, biocides, antioxidants) Reject

Reference Values

Toxoplasma IgM

Negative

 

Toxoplasma IgG

Negative

<1 IU/mL Negative

≥1-<3 IU/mL Borderline

≥3 IU/mL Positive

 

Reference values apply to all ages.

Interpretation

Negative: No IgM or IgG antibodies to Toxoplasma gondii detected. False-negative results may occur in immunocompromised patients or if testing was performed within 1 to 2 weeks of initial exposure and repeat testing may be helpful. A single negative result should not be used to rule out toxoplasmosis, and repeat testing is recommended for patients at high risk for infection.

 

Borderline: Repeat testing on a new sample collected in 2 to 3 weeks is recommended to assess for seroconversion. Further confirmatory testing may be necessary at a Toxoplasma reference laboratory in borderline results persist following repeat testing.

 

Positive: Toxoplasma gondii IgM antibodies detected. Specimens with positive results should be confirmed by a laboratory with expertise in the diagnosis of toxoplasmosis. T gondii IgG antibodies detected, indicating recent or past infection. A significant change in T gondii IgG levels suggests recent infection. For confirmation of toxoplasmosis, the US Food and Drug Administration issued a Public Health Advisory (07/25/1997) that recommends sera found to be positive for T gondii IgM antibodies should be sent to a Toxoplasma reference laboratory.

Method Description

The electrochemiluminescence immunoassay for the in vitro qualitative determination of IgM antibodies to Toxoplasma gondii in human serum is a micro-capture test principle. During the first incubation, 6 mcL of sample are automatically prediluted 1:20 with Diluent Universal. T gondii-specific recombinant antigen labeled with a ruthenium complexa is added. Anti-Toxo IgM antibodies present in the sample react with the ruthenium-labeled T gondii-specific recombinant antigen. In the second incubation, biotinylated monoclonal h-IgM-specific antibodies and streptavidin-coated microparticles are added. The complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell II M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier. Results are determined automatically by the software by comparing the electrochemiluminescence signal obtained from the reaction product of the sample with the signal of the cutoff value previously obtained by calibration.(Package insert: Elecsys Toxo IgM, Roche Diagnostics. GmbH, 01/2024)

 

The electrochemiluminescence immunoassay for the in vitro quantitative determination of IgG antibodies to Toxoplasma gondii in human serum is a sandwich test principle. During the first incubation, 6 mcL of sample a biotinylated recombinant T gondii-specific antigen labeled with a ruthenium complex form a sandwich complex. In the second incubation, streptavidin-coated microparticles are added and the complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell II M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier. Results are determined by a calibration curve which is instrument-specifically generated by 2-point calibration and a master curve provided via the cobas link.(Package insert: Elecsys Toxo IgG, Roche Diagnostics. GmbH, 02/2022)

Day(s) Performed

Monday through Saturday

Report Available

Same day/1 to 3 days

Specimen Retention Time

14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

86778-Toxoplasma IgM

86777-Toxoplasma IgG

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TXPAB Toxoplasma Ab, IgM and IgG, S 88746-3

 

Result ID Test Result Name Result LOINC Value
GTXP Toxoplasma Ab, IgG, S 40677-7
MTXP Toxoplasma Ab, IgM, S 40678-5
DEX04 Toxoplasma IgG Value 8039-0