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Lab Manual for UCSF Clinical Laboratories

Lab Manual for SFGH

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Item Value
Available Stat? No
Test code TOXE
Performed by? Microbiology
Sendout? no
Price range $$
In House Availability test is run 2 times each week: Monday and Thursday.
Principle This assay is an enzyme-linked fluorescent immunoassay for the detection of IgG antibody to Toxoplasma gondii. The purpose of the test is to determine immune status. Results are reported as positive or negative for the presence of antibody.
Method EIA
Interpretation Toxoplasma gondii is an obligate intracellular parasite which can infect a wide range of hosts, including man. The prevalence of Toxoplasma antibodies, indicating past or present infection, varies considerably among different populations and ranges from 3 - 45% within the United States. In studies conducted in the San Francisco Bay area, the prevalence of IgG antibody was found to be 10% in pregnant women in Palo Alto (1987) and 16% in HIV-1 infected males.

Infection of adults is commonly asymptomatic, however, in the immunocompromised patient, recently acquired or reactivated latent infection may be severe to fatal. In the USA most of the toxoplasmosis which occurs in AIDS is due to reactivation of quiescent infection. Only 5% of AIDS patients with intracerebral mass lesions caused by T. gondii lack IgG antibody.
Transplacental transmission, during primary maternal infection, may lead to congenital toxoplasmosis. Maternal infections acquired before conception present little, if any, risk to the fetus. (For information concerning congenital toxoplasmosis refer to "Toxoplasma IgM Antibody.")

IgG antibodies to T. gondii usually appear 1-2 weeks after initiation of infection, reaching peak levels at 6-8 weeks and gradually decline over 1-2 years. Low levels of IgG persist for life, although some patients can have high levels of antibody for years. Patient serum with results of less than 4 IU/mL are reported as negative for presence of Toxoplasma IgG antibody. A positive result is reported for specimens testing ≥ 8 IU/mL, and is indicative of Toxoplasma infection at some undetermined time. Patient results of ≥ 4 IU/mL and < 8 IU/mL are reported as equivocal.
Container type gold top gel tube
Amount to Collect 3 mL
Collection Instructions Grossly hemolyzed or lipemic specimens are not acceptable.
Sample type Serum
Normal range negative
Stability 2 days at 4°C; 1 month at -20°C
Additional information REQUISITION: Blood/Serum - Main Laboratory.
References 1. Dannemann BR, Israelski DM, Leoung GS, McGraw T, Mills J, and Remington RS. Toxoplasma serology, parasitemia, and antigenemia in patients at risk for toxoplasmic encephalitis. 1991. AIDS, 5:1363-1365.

2. Mandell GL, Bennett JE, and Dolin R., Eds. Principles and Practice of Infectious Diseases, 6th ed., Churchill Livingstone, Inc., New York, 2005.

3. Porter SB, Sande MA: Toxoplasmosis of the Central Nervous System in the Acuired Immunodificiency Syndrome. N Engl J Med. 1992 Dec 3: 327(23): 1643-8.
CPT coding 86777
Last Updated 2/20/2009 11:49:58 AM
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