Test Details
Methodology
Chemiluminescent immunoassay (CLIA)
Result Turnaround Time
1 - 2 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
Index result quantitating IgG antibodies
Use
Qualitative determination of IgG antibodies to Toxoplasma gondii (T. gondii) to aid in the determination of immune status of individuals including pregnant women. If IgG antibody is detected, it is recommended that IgM testing be performed if more precise knowledge of the time of infection is needed (e.g., pregnant women). A positive IgM but a negative IgG result should be viewed with suspicion; the patient should be retested two weeks after the first test. If the patient is pregnant and IgG/IgM positive, an IgG avidity test should be performed.
IgG Result | IgM Result | Interpretation |
|---|---|---|
Negative | Negative | No serological evidence of infection with Toxoplasma. |
Negative | Equivocal | Possible early acute infection or false‐positive IgM reaction. Obtain a new specimen for IgG and IgM testing. If results for the second specimen remain the same, the patient is probably not infected with Toxoplasma. |
Negative | Positive | Possible acute infection or false‐positive IgM result. Obtain a new specimen for IgG and IgM testing. If results for the second specimen remain the same, the IgM reaction is probably a false‐positive. |
Equivocal | Negative | Indeterminate. Obtain a new specimen for testing or retest this specimen for IgG in a different assay. |
Equivocal | Equivocal | Indeterminate. Obtain a new specimen for both IgG and IgM testing. |
Equivocal | Positive | Possible acute infection with Toxoplasma. Obtain a new specimen for IgG and IgM testing. If results for the second specimen remain the same or if the IgG becomes positive, specimens should be sent to a laboratory with expertise in toxoplasmosis for further testing. |
Positive | Negative | Infected with Toxoplasma for six months or more. |
Positive | Equivocal | Infected with Toxoplasma for probably more than one year or false‐positive IgM reaction. Obtain a new specimen for IgM testing. If results with the second specimen remain the same, specimens should be sent to a laboratory with expertise in toxoplasmosis for further testing. |
Positive | Positive | Possible recent infection within the last 12 months, or false-positive IgM reaction. Specimens should be sent to a laboratory with expertise in toxoplasmosis for further testing. |
Limitations
This test has not been cleared/approved by the FDA for blood/plasma donor screening.
References
Custom Additional Information
Toxoplasma gondii is endemic in cats and is excreted by them in their feces. Humans are easily exposed to cyst forms, and the majority develop antibody without any clinical disease. A self-limiting lymphadenitis is the most common clinical presentation in symptomatic infection. Congenital toxoplasmosis and infections in AIDS patients are more serious.
Specimen Requirements
Specimen
Serum
Volume
0.5 mL
Minimum Volume
0.2 mL
Container
Red-top tube or gel-barrier tube
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x4 |
Reference Range
• Negative: <6.0 IU/mL
• Equivocal: 6.0−7.9 IU/mL
• Positive: >7.9 IU/mL
Storage Instructions
Room temperature
Causes for Rejection
Hemolysis; lipemia; gross bacterial contamination
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 006478 | Toxoplasma gondii Ab, IgG | 5388-4 | 006483 | Toxoplasma gondii Ab,IgG | IU/mL | 5388-4 |
| Order Code | 006478 | |||||
| Order Code Name | Toxoplasma gondii Ab, IgG | |||||
| Order Loinc | 5388-4 | |||||
| Result Code | 006483 | |||||
| Result Code Name | Toxoplasma gondii Ab,IgG | |||||
| UofM | IU/mL | |||||
| Result LOINC | 5388-4 |