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Test Code LAB0232405 Toxoplasma gondii Antibody, IgM and IgG, Serum

Additional Codes

Mayo Test ID
TXMGP

Useful For

Determining whether a patient has had previous exposure to or recent infection with Toxoplasma gondii

 

IgG is not useful for diagnosing infection in infants younger than 6 months of age. IgG antibodies in this age group usually are the result of passive transfer from the mother.

Profile Information

Test ID Reporting Name Available Separately Always Performed
TXM Toxoplasma Ab, IgM, S Yes Yes
TOXGP Toxoplasma Ab, IgG, S Yes Yes

Method Name

Multiplex Flow Immunoassay (MFI)

Reporting Name

Toxoplasma Ab, IgM and IgG, S

Specimen Type

Serum


Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Aliquot tube

Specimen Volume: 1.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.8 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 14 days
  Frozen  14 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Heat-inactivated specimen Reject

Reference Values

Toxoplasma IgM

Negative

 

Toxoplasma IgG

Negative

 

Toxoplasma IgG Value

≤9 IU/mL (Negative)

10-11 IU/mL (Equivocal)

≥12 IU/mL (Positive)

Reference values apply to all ages.

Interpretation

Active toxoplasmosis is suggested by the presence of IgM-class antibodies, but elevated anti-IgM titers may be absent in patients who are immunocompromised. In addition, elevated IgM can persist from an acute infection that may have occurred as long ago as 1 year. A suspected diagnosis of acute toxoplasmosis should be confirmed by detection of Toxoplasma gondii DNA by polymerase chain reaction (PCR) analysis of cerebrospinal fluid or amniotic fluid specimens (PTOX / Toxoplasma gondii, Molecular Detection, PCR, Varies).

 

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.

 

A single negative result should not be used to rule-out toxoplasmosis, and repeat testing is recommended for patients at high risk for infection.

 

IgG is only indicative of previous exposure to Toxoplasma (recent or past). A single positive Toxoplasma IgG result should not be used to diagnose recent infection. Seroconversion from negative to positive IgG is indicative of recent T gondii infection.

Day(s) Performed

Monday through Saturday

Report Available

Same day/1 to 3 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
TXMGP Toxoplasma Ab, IgM and IgG, S 88746-3

 

Result ID Test Result Name Result LOINC Value
TOXG Toxoplasma Ab, IgG, S 40677-7
TXM Toxoplasma Ab, IgM, S 40678-5
DEXG6 Toxoplasma IgG Value 8039-0

Specimen Retention Time

14 days

Forms

If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.