Lab Test

Toxoplasma IgG

Toxoplasma Antibody, IgG

Test Codes

EPIC: LAB6891, Beaker: TOXIG


Special Chemistry

Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 2.0 mL)

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within two hours of collection. (Minimum Serum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged collection tube, refrigerated (2-8 °C or 36-46 °F). (Minimum Serum: 0.5 mL)

Rejection Criteria

  • Plasma specimens. 
  • Lipemic, icteric, or grossly hemolyzed specimens.  

In-Lab Processing

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Room temperature is acceptable for a maximum of two hours. (Minimum Serum: 0.5 mL)


Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers® with Separator Gels
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 72 hours
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers® without Separator Gels
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 6 months

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days


Royal Oak Special Testing Laboratory


Tuesday, Friday.
Results available in 2 business days.

Reference Range

Negative:  ≤ 9 IU/mL
Equivocal:  10.0-11.0 IU/mL
Positive:  ≥ 12 IU/mL

Test Methodology

Multiplex Flow Assay


  • Positive: A result greater than or equal to 8.8 IU/mL is indicative of a past infection.
  • Negative: A result less than 7.2 IU/mL is considered to be negative and suggestive of no prior exposure.
  • Equivocal: For a result between 7.2 and 8.7 IU/mL, consider repeat testing.

Clinical Utility

This assay is used for the qualitative measurement of IgG antibodies to Toxoplasma gondii in human serum or plasma to determine an acute or past infection.

Clinical Disease

The causative agent of Toxoplasmosis is Toxoplasma gondii, a small intracellular protozoan parasite. Eighty to ninety percent of Toxoplasma infections are asymptomatic. Symptomatic patients may present with cervical lymphadenopathy, fever, sore throat, malaise, rash, or hepatosplenomegaly. Immunodeficient patients may have systemic infection, pneumonia, chorioretinitis, or CNS manifestations such as abscesses, encephalopathy, or encephalitis. Toxoplasmosis during pregnancy may cause spontaneous abortion or disease in the infant with symptoms developing after birth (2).


Toxoplasmosis occurs worldwide. Asymptomatic infections are common. Serological surveys show that 7 to 80% of various populations are infected. The developing fetus and immunocompromised patients are at risk for severe disease (1).


Transmission may occur transplacentally, by ingestion of raw or undercooked meat containing tissue cysts, or by exposure to oocysts in soil contaminated with cat feces (1).


  1. Berkow R, Fletcher A. The Merck Manual of Diagnosis and Therapy 16th edition, Merck Research Laboratories, Rahway, N.J., 1992.
  2. Bakerman S. Bakerman's ABC's of Interpretive Laboratory Data 3rd edition, Interpretive Laboratory Data, Inc., Myrtle Beach, SC, 1994.

CPT Codes

LOINC: 5388-4


Last Updated


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