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.
Use
Qualitative determination of IgM antibodies to Toxoplasma gondii (T. gondii) to aid in the presumptive diagnosis of acute or recent T. gondii infection, including in pregnant women. It is recommended that IgM testing be performed in conjunction with IgG testing. A positive IgM but 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
Low levels of Toxoplasma IgM may persist for months to years after an initial infection. This test has not been cleared/approved by the FDA for blood/plasma donor screening.
References
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: <8.0 AU/mL
• Equivocal: 8.0−9.9 AU/mL
• Positive: >9.9 AU/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 |
|---|---|---|---|---|---|---|
| 096651 | Toxoplasma gondii Ab,IgM | 5390-0 | 096658 | Toxoplasma gondii Ab,IgM | AU/mL | 5390-0 |
| Order Code | 096651 | |||||
| Order Code Name | Toxoplasma gondii Ab,IgM | |||||
| Order Loinc | 5390-0 | |||||
| Result Code | 096658 | |||||
| Result Code Name | Toxoplasma gondii Ab,IgM | |||||
| UofM | AU/mL | |||||
| Result LOINC | 5390-0 |
| Order Code | Order Name | Result Code | Result Name | UofM | Result LOINC | |
|---|---|---|---|---|---|---|
| Reflex 1 | 096659 | Comment: | 096659 | Comment: | N/A | |
| Reflex 1 | ||||||
| Order Code | 096659 | |||||
| Order Name | Comment: | |||||
| Result Code | 096659 | |||||
| Result Name | Comment: | |||||
| UofM | ||||||
| Result LOINC | N/A | |||||
| Order Code | Order Name | Result Code | Result Name | UofM | Result LOINC | |
|---|---|---|---|---|---|---|
| Reflex 1 | 096660 | Comment: | 096660 | Comment: | N/A | |
| Reflex 1 | ||||||
| Order Code | 096660 | |||||
| Order Name | Comment: | |||||
| Result Code | 096660 | |||||
| Result Name | Comment: | |||||
| UofM | ||||||
| Result LOINC | N/A | |||||