(179 days)
The Elecsys Toxo IgG immunoassay is for the in vitro quantitative determination of IgG antibodies to Toxoplasma gondi in human serum and Li-heparin, K3-EDTA, and sodium citrate plasma. This assay is intended for use as an aid in the assessment of immune status and as an aid in the diagnosis of primary infection. The electrochemiluminescence immunoassay "ECLIA" is intended for use on the Elecsys and cobas e immunoassay analyzers. NOTE: This assay has not been cleared by the FDA for blood/plasma donor screening. Elecsys PreciControl Toxo IgG is used for quality control of the Elecsys Toxo IgG immunoassay on the Elecsys and cobas e immunoassay analyzers.
(1) The Elecsys Toxo IgG Immunoassay is a two-step sandwich immunoassay with streptavidin microparticles and electrochemiluminescence detection. In the first incubation, 10 µL of sample, a biotinylated recombinant T. gondii- specific antigen, and a T. gondii-specific recombinant antigen labeled with a ruthenium complex a form a sandwich complex. Then, after addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier. Results are determined via a calibration curve which is instrument-specifically generated by 2-point calibration and a master curve provided via the reagent barcode. A human serum-based calibrator is provided with the test kit, and the recommended control material is PreciControl Toxo IgG. (2) The Elecsys Precicontrol Toxo IgG contains two levels of human serum with Toxo IgG antibodies.
The document describes the Elecsys Toxo IgG Test System, an immunoassay for the quantitative determination of IgG antibodies to Toxoplasma gondii.
Here's an analysis of the acceptance criteria and the study proving the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for each reported performance characteristic are not explicitly stated in a single "acceptance criteria" section. However, based on the reported data, we can infer the criteria used:
| Performance Characteristic | Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|---|
| Method Comparison (vs. Reference Method) | ||
| US Routine Clinical Specimens | ||
| Negative Agreement | High negative agreement | 93.4% (310/332) (90.1%-95.8% CI) |
| Positive Agreement | High positive agreement | 100% (183/183) (98.0%-100.0% CI) |
| European Site Prospective Study | ||
| Negative Agreement | High negative agreement | 91.1% (288/316) (87.5-94.0% CI) |
| Positive Agreement | High positive agreement | 99.3% (151/152) (96.4-100.0% CI) |
| European Site Frozen Samples | ||
| Negative Agreement | High negative agreement | 68.1% (32/47) (52.9-80.9% CI) |
| Positive Agreement | High positive agreement | 99.7% (378/379) (98.5-100.0% CI) |
| Precision | Consistent and low variability | |
| Intrassay (Low Control) | Low SD | SD = 0.02-0.05 IU/mL |
| Intrassay (High Control) | Low CV% | 2.02-4.78 CV % |
| Intrassay (Plasma < 1 IU/mL) | Low SD | 0.014-0.079 SD IU/mL |
| Intrassay (Plasma > 1 IU/mL) | Low CV% | CV 1.76-3.09% |
| Inter-assay (Low Control) | Low SD | SD 0.047 -0.077 IU/mL |
| Inter-assay (High Control) | Low CV% | CV 2.9-5.1 % |
| Inter-assay (Plasma < 5 IU/mL) | Low SD | SD 0.039-0.089 IU/mL |
| Inter-assay (Plasma > 5 IU/mL) | Low CV% | CV 2.7-5.3% |
| Limit of Blank (LoB) | Clearly defined upper limit | 0.130 IU/mL |
| Limit of Detection (LoD) | Clearly defined lower limit | 0.175 IU/mL |
| Analytical Specificity (Cross-reactivity) | No significant cross-reactivity with common interfering substances (e.g., RF, ANA, EBV). Minimal impact from other infections. | No cross-reactivity or interference due to RF, ANA, and EBV. 4 out of 186 non-Toxo samples showed positive by Elecsys Toxo IgG or reference method. |
| Interferences (Icterus, Hemolysis, Lipemia, Biotin) | Recovery of positive samples within ± 20% of initial value. | Unaffected by icterus (< 684 µmol/L), hemolysis (< 1.24 mmol/L), lipemia (< 2000 mg/dL), and biotin (< 246 nmol/L). |
2. Sample Size Used for the Test Set and Data Provenance
- Method Comparison Studies (Test Set):
- US Routine Clinical Specimens: 332 negative samples and 183 positive samples, totaling 515 samples. Data Provenance: "US Routine Clinical Specimens" - suggests a retrospective collection from a US laboratory.
- European Site Prospective Study: 316 negative samples and 152 positive samples, totaling 468 samples. Data Provenance: "European Site Prospective study results" - indicates a prospective collection from a European site.
- European Site Frozen Sample Results: 47 negative samples and 379 positive samples, totaling 426 samples. Data Provenance: "European Site Frozen sample results" - indicates retrospective frozen samples from a European site.
- Analytical Specificity (Cross-reactivity) Study: 193 specimens tested. Data Provenance: Not explicitly stated, but likely from clinical labs, some of which are positive for other conditions.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the "number of experts" or their "qualifications" for establishing the ground truth. The ground truth for the method comparison studies is established by a "reference method" (the predicate device, VIDAS TOXO IgG II Test System, K993319, or other established laboratory methods for classifying positive/negative).
4. Adjudication Method for the Test Set
The document does not describe an adjudication method involving multiple readers or experts for the test set. The comparison is made against a "reference method," implying that the outcome of the reference method serves as the ground truth.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
No MRMC comparative effectiveness study was mentioned. This device is an in vitro diagnostic immunoassay, not an AI-powered diagnostic imaging or interpretation tool that would typically involve human readers and such a study design.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done
Yes, the studies presented (e.g., method comparison, precision, analytical specificity) are all standalone performance evaluations of the Elecsys Toxo IgG Immunoassay itself, without human interpretation as part of the primary diagnostic step. The device provides a quantitative result (IU/mL) which is then used by clinicians, but the performance data reflects the device's inherent analytical capabilities.
7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)
The ground truth used for the method comparison studies is established by a reference method. For a diagnostic immunoassay, this typically means a legally marketed and established laboratory assay considered to be the best available method for determining the presence or absence of Toxoplasma gondii IgG antibodies. The predicate device, VIDAS TOXO IgG II Test System, is explicitly mentioned as the comparison standard, implying it serves as a key component of the ground truth or "reference standard" for comparison.
8. The Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of device development. For an immunoassay, the "training" typically refers to the development and optimization of the assay reagents, protocols, and cut-offs. The clinical samples used for validation are considered "test sets" to evaluate the finalized device performance.
9. How the Ground Truth for the Training Set Was Established
As no specific "training set" is described in the context of a separate study with established ground truth, this information is not available in the provided text. The development process for an immunoassay generally involves extensive analytical validation and optimization using well-characterized samples, which implicitly involve defining known positive and negative samples (ground truth) during development.
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Elecsys Toxo IgG Test System
510(k) Summary
(07350)
| Introduction | According to the requirements of 21 CFR 807.92, the following information provides sufficient detail to understand the basis for a determination of substantial equivalence. |
|---|---|
| Submitter name, address, contact | Roche Diagnostics 9115 Hague Road Indianapolis, IN 46250 (317) 521 - 3723 |
| Contact Person: Theresa A. Bush | |
| Date PreparedJune 6, 2008 | |
| Device Name | |
| Proprietary name: (1) Elecsys Toxo IgG Immunoassay (2) Elecsys PreciControl Toxo IgG | |
| Common name: (1) Toxoplasma IgG assay (2) PreciControl Toxo IgG | |
| Classification name: (1) Toxoplasma gondi serological reagents (2) Single (specified) analyte controls (assayed and unassayed) |
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| Device Description | (1) The Elecsys Toxo IgG Immunoassay is a two-step sandwich immunoassay with streptavidin microparticles and electrochemiluminescence detection. In the first incubation, 10 µL of sample, a biotinylated recombinant T. gondii- specific antigen, and a T. gondii-specific recombinant antigen labeled with a ruthenium complex a form a sandwich complex. Then, after addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier. Results are determined via a calibration curve which is instrument-specifically generated by 2-point calibration and a master curve provided via the reagent barcode. A human serum-based calibrator is provided with the test kit, and the recommended control material is PreciControl Toxo IgG. (2) The Elecsys Precicontrol Toxo IgG contains two levels of human serum with Toxo IgG antibodies. |
|---|---|
| Intended use | (1) The Elecsys Toxo IgG immunoassay is for the in vitro quantitative determination of IgG antibodies to Toxoplasma gondi in human serum and Li-heparin, K3-EDTA, and sodium citrate plasma. This assay may be used as an aid in the assessment of immune status and as an aid in the diagnosis of primary infection. The electrochemiluminescence immunoassay "ECLIA" is intended for use on the Elecsys and cobas e immunoassay analyzers. (2) Elecsys PreciControl Toxo IgG is used for quality control of the Elecsys Toxo IgG immunoassay on the Elecsys and cobas e immunoassay analyzers. |
| Indications for Use | (1) The Elecsys Toxo IgG assay may be used as an aid in the assessment of immune status and as an aid in the diagnosis of primary infection. |
| Substantial equivalence | The Elecsys Toxo IgG Test System is substantially equivalent to the VIDAS TOXO IgG II Test System cleared in K993319 |
510(k) Summary, Continued
Substantial equivalence -
| equivalence |
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| similarities |
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Elecsys Toxo IgG Test System
| Feature | Elecsys Toxo IgG Immunoassay | Predicate Device: VIDAS TOXOIgG II Test System (K993319) |
|---|---|---|
| Intended Use | The Elecsys Toxo IgG immunoassay is forthe in vitro quantitative determination ofIgG antibodies to Toxoplasma gondi inhuman serum and Li-heparin, K3-EDTA,and sodium citrate plasma. This assay isintended for use as an aid in the assessmentof immune status and as an aid in thediagnosis of primary infection.The electrochemiluminescenceimmunoassay "ECLIA" is intended for useon the Elecsys and cobas e immunoassayanalyzers.NOTE: This assay has not been cleared bythe FDA for blood/plasma donor screening. | The VIDAS Toxo IgG II (TXG) assayis an automated quantitative test for useon the VIDAS analyzer for themeasurement of anti-toxoplasma IgGin human serum using the ELFAtechnique (Enzyme LinkedFluorescence Assay). It is intended foruse as an aid in determination ofimmune status. This test is not intendedfor use in screening blood donors. |
| Indication forUse | aid in the assessment of immune status andas an aid in the diagnosis of primaryinfection. | an aid in determination of immunestatus |
| Assay Protocol | Electrochemiluminescent Immunoassay | enzyme-linked fluorescentimmunoassay (ELFA) |
| Sample Type | Human serum, lithium heparin plasma,potassium EDTA plasma and sodium citrateplasma.When citrated plasma is used, the values foundare approximately 15% lower | Serum |
| InstrumentPlatform | Roche Elecsys 2010/ cobas e 411 andMODULAR ANALYTICS E170 (Elecsysmodule)/ cobas e 601 analyzers. | VIDAS ® Instrument |
| Calibrator | Included in kit | Included in kit |
| Calibrator levels | Two | One |
| Format | Human serum | Human serum |
| CalibratorStability | After opening at 2-8C: 8 weeksOn Elecsys 2010/ cobas e 411: up to 5hoursOn E170/ cobas e 601: use only once | Store between 2-8 °C. |
| Calibrationfrequency | Once per reagent lot and• After 1 month when using samereagent lot• After 7 days when using samereagent kit• As required per QC findings orpertinent regulations | • Every new reagent lot• Every 14 days |
| Controls | PreciControl Toxo IgG (sold separately) | Positive and negative control included in kit. |
| Traceability | 3rd International Standard for Anti-Toxoplasma serum (TOXM) from NIBSC,UK | WHO standard |
| Reagent Stability | Unopened 2-8°C - up to expirationOpened 2-8°C - 12 weeksOnboard- 2 weeks or 12 weeks (if storedalternately in refrigerator and on theanalyzer- ambient temperature 20-25°C; upto 84 hours opened in total.) | Unopened kit: Store at 2-8°C. Do notfreezeAfter opening: Store at 2-8°C . Pouchshould be immediately resealed withdessicant ; stable until expiration date |
| MeasuringRange | 0.125-650 IU/mL | Linear up to 250 or 300 IU/mL |
| Precision | Intrassay: (range of values)Low Control: SD = 0.02-0.05 IU/mLHigh Control: 2.02-4.78 CV %Plasma Samples < 1 IU/mL:0.014-0.079 SD IU/mLPlasma Samples > 1 IU/mL:CV 1.76-3.09%Inter-assay:Low Control: SD 0.047 -0.077 IU/mLHigh Control: CV 2.9-5.1 %Plasma Samples < 5 IU/mL:SD 0.039-0.089 IU/mLPlasma Samples > 5 IU/mL:CV 2.7-5.3% | Within-run:Negative: SD = 0.25 IU/mLLow positive: 5.13% CVHigh positive: 7.21 % CVTotal:Negative: SD = 0.43 IU/mLLow positive: 6.70% CVHigh positive: 10.88 % CV |
| Limit of Blank | 0.130 IU/mL | Not stated. |
| Limit ofDetection | 0.175 IU/mL | Not stated. |
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| Analytical Specificity | 193 specimens were tested representing a variety of disease. Results shown in table: | No crossreactivity or interference due to RF, ANA and EBV. | ||||
|---|---|---|---|---|---|---|
| Cross-reactant | No. tested | Elecsys Toxo IgG/Reference Neg/Neg | Elecsys Toxo IgG/Reference Pos/Neg | Elecsys Toxo IgG/Reference Neg/Pos | Elecsys Toxo IgG/Reference Pos/Pos | |
| AMAf | 15 | 3 | 0 | 0 | 11 | |
| ANAg | 26 | 8 | 1 | 0 | 15 | |
| Chlamydia | 4 | 2 | 0 | 0 | 2 | |
| CMV | 8 | 0 | 0 | 0 | 8 | |
| EBVh | 9 | 4 | 0 | 0 | 4 | |
| Gonorrhea | 5 | 2 | 0 | 0 | 3 | |
| HAV | 10 | 7 | 0 | 0 | 3 | |
| HBV | 23 | 14 | 1 | 0 | 8 | |
| HCVi | 11 | 5 | 0 | 0 | 6 | |
| HIV | 13 | 10 | 1 | 0 | 2 | |
| HSVj | 8 | 1 | 0 | 0 | 6 | |
| Influenza | 16 | 12 | 0 | 0 | 4 | |
| Malaria | 10 | 4 | 0 | 0 | 6 | |
| Parvo B19 | 10 | 9 | 0 | 0 | 1 | |
| Rubella | 10 | 4 | 0 | 0 | 6 | |
| Syphilis | 5 | 3 | 0 | 0 | 2 | |
| TPAH | 3 | 1 | 0 | 0 | 1 | |
| VZV | 7 | 4 | 1 | 0 | 2 | |
| Sub-total | 186 | 93 | 4 | 0 | 89 | |
| Total | 193 | |||||
| f. One sample was repeatedly equivocal by the Elecsys Toxo IgG immunoassay | ||||||
| g. Two samples were repeatedly equivocal by the reference method | ||||||
| h One sample was repeatedly equivocal by the reference method | ||||||
| i One sample was repeatedly equivocal by the Elecsys Toxo IgG immunoassay | ||||||
| j One equivocal sample was not repeated on the reference method | ||||||
| Interferences | The assay is unaffected by icterus (bilirubin $< 684$ µmol/L or $< 40$ mg/dL), hemolysis (Hb $< 1.24$ mmol/L or $< 2$ g/dL), lipemia (Intralipid $< 2000$ mg/dL), and biotin $< 246$ nmol/L or $< 60$ ng/mL.Criterion: Recovery of positive samples within ± 20% of initial value.Rheumatoid factor was not observed to cause any consistent bias. However, elevated levels of RF may lead to erroneous results in some instances No interference due to 18 commonly used pharmaceuticals or to spiramycine, sulfadiazine, folic acid, and pyrimethamine. | Avoid using obviously hemolyzed, lipemic, or icteric samples. | ||||
| Expected Values | In a prospective study of 515 subjects from a United States reference laboratory, the prevalence of IgG antibodies to T. gondii was shown to be 37.1%. The prevalence was 42.7% in pregnant women, 43.6% in males, 36.6% in females.The prevalence from a European study of 470 prospectively collected samples was 37.4%. The prevalence was 9.6% in pregnant women, 41.2% in males and 11.2% in females. Prevalence in the group | The prevalence of toxoplasmosis varies depending upon geographical location, age and gender of the population studied, specimen collection and handling, and other factors. In Europe, the prevalence rate ranges from 20% to 85%. In the United States, the prevalence is lower: 12% to 41%. Prevalence in other countries can vary from 18% to 65% |
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| Method Comparison | |
|---|---|
| US Routine Clinical Specimens | |
| Negative Agreement: 93.4 % (310/332) 90.1%-95.8% | |
| Positive Agreement 100 % (183/183) 98.0% - 100.0% | |
| European Site Prospective study results: | |
| Negative Agreement: 91.1% (288/316) 87.5 - 94.0 % | |
| Positive Agreement: 99.3% (151/152) 96.4-100.0% | |
| European Site Frozen sample results: | |
| Negative Agreement: 68.1 (32/47) 52.9 -80.9% | |
| Positive Agreement: 9999.7% (378/379) 98.5-100.0 |
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Public Health Service
Image /page/6/Picture/2 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized graphic of three wavy lines, which are meant to represent the human form. The graphic is surrounded by the text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" arranged in a circular fashion.
Food and Drug Administration 2098 Gaither Road Rockville MD 20850
Ms. Theresa Bush Regulatory Affairs Principal Roche Diagnostics 9115 Hague Road Indianapolis, IN 46250
JUN - 9 2008
Re: K073501 Trade/Device Name: Elecsys® Toxo IgG Immunoassay and Elecsys® PreciControl Toxo IgG Regulation Number: 21 CFR 866.3780 21 CFR 862.1660 Regulation Name: Toxoplasma gondii Serological Reagents Quality Control Material (assayed and unassayed) Regulatory Class: Class II Product Code: LGD, JJX Dated: April 30, 2008 Received: May 1, 2008
Dear Ms. Bush:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21, Code of Federal Regulations (CFR), Parts 800 to 895. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any reveral statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); and good manufacturing (2) Cr rule 807); fabeling (21 CFK Paris 80) and good manufacturing (OS) requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820).
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This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at 240-276-0450. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding postmarket surveillance, please contact CDRH's Office of Surveillance and Biometric's (OSB's) Division of Postmarket Surveillance at 240-276-3474. For questions regarding the reporting of device adverse events (Medical Device Reporting (MDR)), please contact the Division of Surveillance Systems at 240-276-3464. You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (240) 276-3150 or at its Internet address http://www.fda.gov/cdrh/industry/support/index.html.
Sincerely yours,
Sally attym
Sally A. Hojvat, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known):
Device Name: Elecsys® Toxo IgG Immunoassay
Indications For Use:
The Elecsys Toxo IgG immunoassay is for the in vitro quantitative determination of IgG antibodies to Toxoplasma gondi in human serum and Li-heparin, K3-EDTA, and sodium citrate plasma. This assay is intended for use as an aid in the assessment of immune status and as an aid in the diagnosis of primary infection.
The electrochemiluminescence immunoassay "ECLIA" is intended for use on the Elecsys and cobas e immunoassay analyzers.
NOTE: This assay has not been cleared by the FDA for blood/plasma donor screening.
| Prescription Use XXX | And/Or | Over the Counter Use _ |
|---|---|---|
| (21 CFR Part 801 Subpart D) | (21 CFR Part 801 Subpart C) |
(PLEASE DO NOT WRITE BELOW THIS LINE; CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of In Vitro Diagnostic Device Evaluation and Safety (OIVD)
Freddie Poole
Division Sign-Off Office of In Vitro Diagnostic Device Evaluation and Safety
510(k) K073521
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Indications for Use
510(k) Number (if known): Ko 7 350 1
Device Name: Elecsys PreciControl Toxo IgG
Indications For Use:
Elecsys PreciControl Toxo IgG is used for quality control of the Elecsys Toxo IgG immunoassay on the Elecsys and cobas e immunoassay analyzers.
Prescription Use XXX (21 CFR Part 801 Subpart D) And/Or
Over the Counter Use _ (21 CFR Part 801 Subpart C)
(PLEASE DO NOT WRITE BELOW THIS LINE; CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of In Vitro Diagnostic Device Evaluation and Safety (OVD)
Freddie La Roche
Division Sign-Off Office of In Vitro Diagnostic Device Evaluation and Safety
510(k) KD73501
§ 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).