(192 days)
IMMULITE® Toxoplasma IgM - For in vitro diagnostic use with the IMMULITE® Analyzers - for the presumptive qualitative detection of IgM antibodies to Toxoplasma gondii in human serum, particularly for women of childbearing age. When performed in conjunction with a Toxoplasma IgG assay, the IMMULITE® Toxoplasma IgM can be used as an aid in the presumptive diagnosis of acute, recent or reactive Toxoplasma gondii infection. This product has not been cleared/approved by the FDA for blood/plasma donor screening.
IMMULITE® 2000 Toxoplasma IgM - For in vitro diagnostic use with the IMMULITE® 2000 Analyzers - for the presumptive qualitative detection of IgM antibodies to Toxoplasma gondii in human serum, particularly for women of childbearing age. When performed in conjunction with a Toxoplasma IgG assay, the IMMULITE® 2000 Toxoplasma IgM can be used as an aid in the presumptive diagnosis of acute, recent or reactive Toxoplasma gondii infection. This product has not been cleared/approved by the FDA for blood/plasma donor screening.
IMMULITE and IMMULITE 2000 Toxoplasma IgM are clinical devices for use with their respective IMMULITE and IMMULITE 2000 Automated Immunoassay Analyzers.
IMMULITE Toxoplasma IgM is a solid-phase, two-step chemiluminescent enzyme immunoassay. The solid phase, a polystyrene bead enclosed within an IMMULITE Test Unit, is coated with partially purified Toxoplasma gondii antigen.
IMMULITE 2000 Toxoplasma IgM is a solid-phase, two-step chemiluminescent enzyme immunoassay. The solid phase, a polystyrene bead added to an IMMULITE 2000 Reaction Tube, is coated with partially purified Toxoplasma gondii antigen.
Here's a breakdown of the acceptance criteria and study information for the IMMULITE® and IMMULITE® 2000 Toxoplasma IgM devices, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are not explicitly stated as quantitative targets (e.g., "sensitivity must be > X%") in the document. Instead, the studies demonstrate "substantial equivalence" to predicate devices (Vidas Toxo IgM and Zeus Scientific Toxo IgM ELISA Test System). The performance is reported as agreement percentages with these predicate devices and with a CDC panel.
| Metric (Acceptance Criteria - Implied by Substantial Equivalence) | IMMULITE Toxoplasma IgM (Reported Performance) | IMMULITE 2000 Toxoplasma IgM (Reported Performance) |
|---|---|---|
| Agreement with Predicate Device (Zeus Scientific Toxo IgM ELISA Test System) | ||
| Positive Agreement (All subjects) | 90.0% (36/40, 95% CI: 76.3% - 97.2%) | 95.0% (38/40, 95% CI: 83.1% - 99.4%) |
| Negative Agreement (All subjects) | 100% (116/116, 95% CI: 96.9% - 100%) | 100% (115/115, 95% CI: 96.8% - 100%) |
| Overall Agreement (All subjects) | 97.4% (152/156, 95% CI: 93.6% - 99.3%) | 98.7% (153/155, 95% CI: 95.4% - 99.8%) |
| Positive Agreement (Pregnant subjects) | 91.7% (22/24, 95% CI: 73.0% - 99.0%) | 95.8% (23/24, 95% CI: 78.9% - 99.9%) |
| Negative Agreement (Pregnant subjects) | 100% (58/58, 95% CI: 93.8% - 100%) | 100% (58/58, 95% CI: 93.8% - 100%) |
| Overall Agreement (Pregnant subjects) | 97.6% (80/82, 95% CI: 91.5% - 99.7%) | 98.8% (81/82, 95% CI: 93.4% - 100%) |
| Agreement with Predicate Device (Vidas Toxo IgM) | (Not tested against Vidas Toxo IgM for IMMULITE 2000) | |
| Positive Agreement (All subjects) | 96.6% (28/29, 95% CI: 82.2% - 99.9%) | N/A |
| Negative Agreement (All subjects) | 95.3% (122/128, 95% CI: 90.1% - 98.3%) | N/A |
| Overall Agreement (All subjects) | 95.5% (150/157, 95% CI: 91.0% - 98.2%) | N/A |
| Positive Agreement (Pregnant subjects) | 100% (16/16, 95% CI: 79.4% - 100%) | N/A |
| Negative Agreement (Pregnant subjects) | 94.1% (64/68, 95% CI: 85.6% - 98.4%) | N/A |
| Overall Agreement (Pregnant subjects) | 95.2% (80/84, 95% CI: 88.3% - 98.7%) | N/A |
| Agreement with CDC Toxoplasma 1998 Human Serum Panel | ||
| Total Agreement | 97.9% | 99.0% |
| Positive Specimens Agreement | 93.8% | 96.9% |
| Negative Specimens Agreement | 100% | 100% |
| Precision (Total CV across sites) | ||
| IMMULITE Toxoplasma IgM Serum Ratio (Example: Sample 1) | 11.1% (Site 1), 6.2% (Site 2), 4.9% (Site 3) | N/A |
| IMMULITE 2000 Toxoplasma IgM Serum Ratio (Example: Sample 1) | N/A | 2.4% (Site 1), 4.3% (Site 2) |
| Cross-Reactivity (vs. various pathogens & RF) | All negative results | All negative results |
| Interference (Bilirubin, Lipemia, Hemoglobin) | No effect observed up to tested concentrations | No effect observed up to tested concentrations |
2. Sample Sizes Used for the Test Set and Data Provenance
- IMMULITE Toxoplasma IgM (vs. Zeus Scientific):
- Sample Size: 172 samples (from apparently healthy male/female subjects, pregnant women, and patients suspected of being toxoplasma IgM positive).
- Data Provenance: Retrospective, samples were frozen. Collected from a clinical study in the southern United States.
- IMMULITE Toxoplasma IgM (vs. Vidas Toxo IgM):
- Sample Size: 168 samples (from apparently healthy male/female subjects, pregnant women, and patients suspected of being toxoplasma IgM positive).
- Data Provenance: Retrospective, samples were frozen. Collected from a clinical study in the northeastern United States.
- IMMULITE 2000 Toxoplasma IgM (vs. Zeus Scientific):
- Sample Size: 172 samples (from normal male/female subjects, pregnant women, and patients suspected of being toxoplasma IgM positive).
- Data Provenance: Retrospective, samples were frozen. Collected from a clinical study in the southern United States.
- IMMULITE 2000 Toxoplasma IgM (vs. IMMULITE Toxoplasma IgM):
- Sample Size: 291 samples.
- Data Provenance: Conducted at DPC (in-house).
- CDC Toxoplasma 1998 Human Serum Panel:
- Sample Size: 97 samples (32 positive, 65 negative).
- Data Provenance: From the CDC (a characterized, masked serum panel).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not explicitly state the number or qualifications of experts used to establish the ground truth for the clinical study samples. The primary method for establishing ground truth in these studies was comparison to predicate devices (Zeus Scientific Toxo IgM ELISA Test System and Vidas Toxo IgM), which are themselves diagnostic assays.
For the CDC Toxoplasma 1998 Human Serum Panel, the ground truth was established by the CDC, meaning the samples were already "characterized." The specific number or qualifications of experts involved in the CDC's characterization are not provided in this document.
4. Adjudication Method for the Test Set
The document describes comparisons between the new devices and predicate devices. No formal "adjudication method" involving human expert review to resolve discrepancies is mentioned for the clinical study samples. Instead, indeterminate results were excluded from agreement calculations. For the CDC panel, it was a "masked, characterized serum panel," implying the CDC's own established results were used as truth without further adjudication by the sponsor.
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
This document describes the performance of in vitro diagnostic assays (chemiluminescent enzyme immunoassays) for detecting antibodies in serum, not an AI-assisted diagnostic device that would typically involve human readers interpreting images or data. Therefore, an MRMC comparative effectiveness study, and the concept of "human readers improve with AI," is not applicable to this device.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
This describes a standalone assay. The IMMULITE and IMMULITE 2000 systems are automated immunoassay analyzers. While they require human operation for sample loading and result interpretation, the measurement of the signal and calculation of the signal/cutoff ratio (the quantitative result of the device) is performed by the instrument itself without human "reading" of the raw immunological reaction. The comparison studies cited are effectively standalone performance studies relative to other standalone diagnostic assays.
7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)
The primary type of ground truth used for the clinical performance studies was the results from legally marketed predicate diagnostic devices (Zeus Scientific Toxo IgM ELISA Test System and Vidas Toxo IgM). For the CDC panel, the ground truth was the CDC's characterization of its serum panel. These are essentially reference assay results, not explicitly pathology, expert consensus (beyond the assay's own validation), or patient outcomes data.
8. The Sample Size for the Training Set
The document does not specify a separate training set for the device. This is typical for traditional in vitro diagnostic assays (like immunoassays) which are developed and validated rather than "trained" in the machine learning sense. The "development" of such assays usually involves optimization using various panels, but a distinct "training set" as understood in AI/ML is not a concept explicitly applied or reported here. The performance studies presented are essentially validation/test sets for demonstrating substantial equivalence.
9. How the Ground Truth for the Training Set Was Established
As no explicit "training set" is mentioned in the context of machine learning, this question is not applicable in the same way it would be for an AI device. The ground truth for the validation/test sets (as described in point 7) was established by comparing the devices' results to predicate devices and a characterized CDC panel.
§ 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).