(168 days)
The ADVIA Centaur Toxoplasma IgG assay is an IgG antibody capture microparticle direct chemiluminometric immunoassay for the quantitative or qualitative detection of IgG antibodies to the Toxoplasma gondii parasite in human serum qualitative EDTA, heparin) using the ADVIA Centaur System. The measurement of Toxoplasma IgG may be used to aid in the assessment of a patient's serological response from individuals including women of childbearing age. This assay may also be utilized with an IgM Toxoplasma result to determine recent serological response to Toxoplasma..
Testing should not be performed as a screening procedure for the general population.
This assay has not been cleared or approved by the FDA for the screening of blood or plasma donors.
Toxoplasma gondii is an intracellular parasitic protozoan that affects birds and mammals, with cats being the primary host. Infection is typically spread by eating raw or undercooked meat containing cysts or by coming in contact with oocyst-infected cat feces. Climate, dietary customs, and presence of cats influence the prevalence of T. gondii, which can vary considerably by geographical location and age. In healthy immunocompetent individuals, infections are usually asymptomatic or subclinical. If toxoplasmosis is diagnosed during the early stages of infection, the disease can be treated effectively with antibiotic therapy.
In pregnant women, T. gondii infection poses a potential threat to the fetus. The risk of a pregnant woman passing infection to the fetus is approximately 25% in the first trimester and increases to approximately 65% in the third trimester. The earlier in the pregnancy that the mother is infected the greater the potential severity of congenital toxoplasmosis. If the fetus becomes infected, the infant may have symptoms such as lymphadenopathy, chorioretinitis, microcephaly and cerebral calcifications. In immunosuppressed populations, such as cancer patients undergoing chemotherapy, transplants recipients, and AIDS patients, T. gondii has emerged as an important opportunistic pathogen leading to severe or fatal infections. The immunosuppressed state of these patients is thought to allow reactivation of a latent infection, and these patients may present symptoms such as headaches, confusion, fever, and focal neurological deficits.
Use of toxoplasma IgG assays has been shown to be a reliable method for establishing immune status and evaluating susceptibility to T. gondii infection. The presence of IgG antibodies that the individual has been infected with toxoplasma in the past, but the level of reactivity does not indicate how recently the infection occurred. In the majority of AIDS patients, the IgG response to primary T. gondii infection often lacks a significant rise in IgG titers.
The ADVIA Centaur Toxoplasma G assay is an immunoglobulin class-capture sandwich immunoassay using direct, chemiluminometric technology. The anti-human IgGFc monoclonal antibody is covalently coupled to paramagnetic particles in the Solid Phase. In the Lite Reagent, the purified T. gondii antigen is bound to an anti-p30 monoclonal labeled with acridinium ester. Antibody-antigen complexes will form if toxoplasma IgG is present in the sample.
A direct relationship exists between the amount of toxoplasma IgG activity present in the patient sample and the amount of relative light units (RLUs) detected by the system. A result of positive or negative is determined using a clinical cutoff value of 10 IU/mL.
The provided text describes the performance characteristics of the Bayer Diagnostics ADVIA Centaur Toxoplasma IgG assay. The acceptance criteria are implicitly derived from the reported performance metrics, particularly "Relative Sensitivity and Specificity" and "CDC Panel" results.
Here's a breakdown of the requested information:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are not explicitly stated as target values in the document. However, based on the provided results and the context of a 510(k) submission for substantial equivalence, the reported performance values are what the manufacturer submitted as demonstrating sufficient accuracy relative to a predicate device and a reference panel. The table below uses the "Total" values from the "Relative Sensitivity, Specificity, and Agreement Before Resolution of Discordant Samples" section and the "CDC Panel" results as key performance indicators.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| Relative Sensitivity | High (e.g., above 90-95%) compared to predicate EIA | 96.5% (363/376) with 95% CI (94.16 - 98.15) |
| Relative Specificity | High (e.g., above 95-98%) compared to predicate EIA | 98.6% (1370/1389) with 95% CI (97.9 - 99.2) |
| Relative Agreement | High (e.g., above 95%) compared to predicate EIA | 98.2% (1733/1765) with 95% CI (97.5 - 98.8) |
| CDC Panel Agreement | High agreement with CDC's characterized panel (especially for positives and negatives) | Total: 98%, Positive: 97% (68/70), Negative: 100% (30/30) |
| Precision (Total %CV) | Low Variability across different concentrations (e.g., |
§ 866.3780
Toxoplasma gondii serological reagents.(a)
Identification. Toxoplasma gondii serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies toToxoplasma gondii in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identifyToxoplasma gondii from clinical specimens. The identification aids in the diagnosis of toxoplasmosis caused by the parasitic protozoanToxoplasma gondii and provides epidemiological information on this disease. Congenital toxoplasmosis is characterized by lesions of the central nervous system, which if undetected and untreated may lead to brain defects, blindness, and death of an unborn fetus. The disease is characterized in children by inflammation of the brain and spinal cord.(b)
Classification. Class II (performance standards).