Test Catalog

Test ID: TOXO    
Toxoplasma Immunostain, Technical Component Only

Useful For Suggests clinical disorders or settings where the test may be helpful

Identification of Toxoplasma gondii infection

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Immunohistochemical staining for Toxoplasma gondii can help identify the organisms in the cytoplasm of infected cells. T gondii is a sporozoan that lives as an intracellular parasite in various tissues of vertebrates. T gondii is transmitted via raw or undercooked meat, contaminated soil, or by direct contact. Pregnant women and immunosuppressed patients are at highest risk for infection.

Interpretation Provides information to assist in interpretation of the test results

This test does not include pathologist interpretation; only technical performance of the stain is performed. If an interpretation is required, order PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case.


The positive and negative controls are verified as showing appropriate immunoreactivity and documentation is retained at Mayo Clinic Rochester. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request, call 855-516-8404.


Interpretation of this test should be performed in the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen-dependent. Best practice is for paraffin sections to be cut within 6 weeks.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Mostafa NES, Abdel Hamed EF, Rashed HES, Mohamed SY, Abdelgawad MS, Elasbali AM: The relationship between toxoplasmosis and different types of human tumors. J Infect Dev Ctries. 2018 Feb 28;12(2):137-141

2. Arnold SJ, Kinney MC, McCormick MS, Dummer S, Scott MA: Disseminated toxoplasmosis. Unusual presentations in the immunocompromised host. Arch Pathol Lab Med. 1997;121(8):869-873

3. Held TK, Kruger D, Switala AR, et al: Diagnosis of toxoplasmosis in bone marrow transplant recipients: comparison of PCR-based results and immunohistochemistry. Bone Marrow Transplant. 2000;25(12):1257-1262