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HelpTest Code TXMGP Toxoplasma gondii Antibody, IgM and IgG, Serum
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, SSpecimen Type
SerumSpecimen 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 |
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.
Clinical Reference
1. Tenter AM, Heckeroth AR, Weiss LM: Toxoplasma gondii: from animals to humans. Int J Parasitol. 2000 Nov;30(12-13):1217-1258
2. Jones JL, Kruszon-Moran D, Rivera HN, Price C, Wilkins PP: Toxoplasma gondii seroprevalence in the United States 2009-2010 and comparison with the past two decades. Am J Trop Med Hyg. 2014 Jun;90(6):1135-1139
3. Luft BJ, Remington JS: Toxoplasmic encephalitis in AIDS. Clin Infect Dis. 1992 Aug;15(2):211-222
4. Wong SY, Remington JS: Toxoplasmosis in pregnancy. Clin Infect Dis. 1994 Jun;18(6):853-861
5. Wang ZD, Liu HH, Ma ZX, et al: Toxoplasma gondii infection in immunocompromised patients: A systematic review and meta-analysis. Front Microbiol. 2017 Mar 9;8:389
Day(s) Performed
Monday through Saturday
Report Available
Same day/1 to 3 daysPerforming 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 |
Forms
If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.