Test ID: TOXOG
Toxoplasma Antibody, IgG, Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Indication of past or recent infection with Toxoplasma gondii
Method Name A short description of the method used to perform the test
Enzyme-Linked Fluorescence Assay (ELFA)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Torch -> if pt age is >6 months order the following:
Toxoplasmosis
Toxoplasma, IgG Antibody, Serum
Toxoplasma gondii (T. gondii)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 0.5 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 14 days |
| Frozen | 14 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Toxoplasma gondii is an obligate intracellular parasite that is capable of infecting a variety of intermediate hosts including humans. Infected definitive hosts (cats) shed oocysts in feces that rapidly mature in soil and become infectious. Toxoplasmosis is acquired by humans via ingestion of food or water contaminated with cat feces or undercooked meats containing oocysts.
Infection of the normal adult is commonly asymptomatic. In cases with clinical manifestations, the most common symptom is lymphadenopathy that may be accompanied by an array of other symptoms making differential diagnosis difficult.
Severe-to-fatal infections do occur in adults immunocompromised by cancer chemotherapy or other immunosuppressive treatment and in patients with AIDS. These infections are thought to be caused by reactivation of latent infections and often involve the central nervous system.
Transplacental transmission of the parasites resulting in congenital toxoplasmosis can occur during the acute phase of acquired maternal infection. The risk of fetal infection is a function of the time at which acute maternal infection occurs during gestation. The incidence of congenital toxoplasmosis increases as pregnancy progresses; conversely, the severity of congenital toxoplasmosis is greatest when maternal infection is acquired early during pregnancy. A majority of infants infected in utero are asymptomatic at birth, particularly if maternal infection occurs during the third trimester, with sequelae appearing later in life. Congenital toxoplasmosis results in severe generalized or neurologic disease in about 20% to 30% of the infants infected in utero; approximately 10% exhibit ocular involvement only and the remainder are asymptomatic at birth. Subclinical infection may result in premature delivery and subsequent neurologic, intellectual, and audiologic defects.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
<4 IU/mL (negative)
4-7 IU/mL (equivocal)
> or =8 IU/mL (positive)
Interpretation Provides information to assist in interpretation of the test results
Diagnosis of acute central nervous system, intrauterine, or congenital toxoplasmosis is difficult by routine serological methods. A single positive IgG result is only indicative of exposure to toxoplasma at some point in time (past or recent) and is present in up to 70% of the adult United States population.
The absence of IgG is helpful in that it usually indicates the absence of infection. However, a negative result could mean either no previous exposure or could also be seen in cases of remote exposure with subsequent loss of detectable antibody.
Seroconversion from negative to positive IgG is indicative of recent Toxoplasma gondii infection. Seroconversion indicates infection subsequent to the first negative specimen.
Specimens interpreted as equivocal may contain very low levels of IgG. A second specimen should be drawn and tested.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
IgG is not useful for diagnosing infection in infants <6 months of age. IgG antibodies in that age group, are usually the result of passive transfer from the mother. A single Toxoplasma IgG antibody assay cannot be used to diagnose recent infection.
The IgM assay TOXOM/8865 Toxoplasma Antibody, IgM, Serum should be used to diagnose an acute infection with Toxoplasma gondii.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Luft BJ, Remington JS: Toxoplasmic encephalitis in AIDS. Clin Infect Dis 1992 August;15(2):211-222
2. Wong SY, Remington JS: Toxoplasmosis in pregnancy. Clin Infect Dis 1994 June;18(6):853-862
Method Description Describes how the test is performed and provides a method-specific reference
The VIDAS TOXO IgG and IgM systems (bioMerieux Inc., Hazelwood, MO) are automated serologic tests for use on the VIDAS analyzer employing the enzyme-linked fluorescence assay (ELFA) technique. The assay combines a 2-step enzyme immunoassay sandwich method with a final fluorescence detection. (Wilson M, Remington J, Clavet C, et al: Evaluation of six commercial kits for detection of human immunoglobulin M antibodies to Toxoplasma gondii. J Clin Microbiol 1997 Dec;35[12]:3112-3115; Hofgartner W, Swanzy S, Bacina R, et al: Detection of immunoglobulin G [IgG] and IgM antibodies to Toxoplasma gondii: evaluation of four commercial immunoassay systems. J Clin Microbiol 1997 Dec;35[12]:3313-3315)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Saturday; 9 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
86777
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| TOXOG | Toxoplasma Ab, IgG, S | 5388-4 |
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