Home
HelpTest Code TXMGP Toxoplasma gondii Antibody, IgM and IgG, Serum
Reporting Name
Toxoplasma Ab, IgM and IgG, SPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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.
Method Name
Multiplex Flow Immunoassay (MFI)
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 Type
SerumSpecimen 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 daysTest 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.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 |
Forms
If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| TXM | Toxoplasma Ab, IgM, S | Yes | Yes |
| TOXGP | Toxoplasma Ab, IgG, S | Yes | Yes |