TOXOPLASMA IGG IN-VITRO DIAGNOSTIC SYSTEM

• K Number: K955760
• Device Name: TOXOPLASMA IGG IN-VITRO DIAGNOSTIC SYSTEM
• Manufacturer: BAYER CORP.
• Date Cleared: 1996-08-02 ( 226 days)
• Product Code: LGD
• Regulation Number: 866.3780
• Type: Traditional
• Panel: MI
• Reference & Predicate Devices: K902409
• Predicate For: N/A

Intended Use

This in vitro diagnostic method in intended to quantitatively and qualitatively measure Toxoplasma IgG in human serum on the Technicon Immuno 10 System. Measurements of Toxoplasma IgG are designed to aid in the determination of serological status by detecting IgG class antibodies to Toxoplasma gondii in human sera. The Technicon Immuno 1 Toxoplasma IgG method is not intended for use in screening blood or plasma donors. The method is intended for in vitro diagnostic use only on the Technicon IMMUNO 1® system.

Device Description

Not Found

AI/ML Overview

Here's an analysis of the acceptance criteria and study details for the TECHNICON TOXOPLASMA IgG METHOD FOR THE IMMUNO 1® SYSTEM, based on the provided document:

Acceptance Criteria and Device Performance

The core performance of the device is assessed against a similar device previously cleared by the FDA: the Abbott IMx Toxoplasma IgG assay. The acceptance criteria are implicit in the comparative study, aiming to demonstrate substantial equivalence in terms of sensitivity, specificity, and overall agreement.

Table 1: Acceptance Criteria and Reported Device Performance

Performance Metric	Acceptance Criteria (Implicit)	Reported Device Performance (IFA Resolved, Combined Clinical Sites & Lots)
Sensitivity	Comparable to Abbott IMx	Lot 1: 96.8% (95% CI: 93.2 - 98.8%)
Lot 2: 95.2% (95% CI: 91.1 - 97.8%)
Specificity	Comparable to Abbott IMx	Lot 1: 96.7% (95% CI: 94.5 - 98.2%)
Lot 2: 96.5% (95% CI: 94.2 - 98.1%)
Overall Agreement	Comparable to Abbott IMx	Lot 1: 96.8% (95% CI: 95.0 - 98.0%)
Lot 2: 96.1% (95% CI: 94.2 - 97.5%)
Linearity	Demonstrated over 12-300 IU/mL	R-values generally >= 0.99 for individual patients (Table 7)
Interference	No clinically significant effect	Hemolyzed (up to 1000 mg/dL), lipemic (up to 900 mg/dL), icteric (up to 25 mg/dL), and various common antibodies showed no significant interference.
Correlation with WHO Standard (TOXS-60)	High correlation (Figure 1)	Y = 0.905 X + 1.618, R² = 0.9998

Study Proving Device Meets Acceptance Criteria:

The study conducted to prove the device meets acceptance criteria is a method comparison study against the Abbott IMx Toxoplasma IgG assay, combined with linearity and interference studies.

The comparative data was collected at two outside clinical trial sites:

• University of Texas Medical Branch, Laboratory Medical Clinical Chemistry, Galveston, Texas
• San Francisco General Hospital Clinical Laboratories, San Francisco, California

Two lots of Immuno 1® Toxoplasma IgG reagents were evaluated at each clinical site.

Detailed Study Information:

1. Table of Acceptance Criteria and Reported Device Performance: (See table above)

2. Sample Size Used for the Test Set and Data Provenance:

   • Test Set Sample Size: For the comparative study with Abbott IMx, the combined test set size across both clinical sites and reagent lots (after IFA resolution) was 585 specimens (188 positive, 397 negative for both Lot 1 and Lot 2).
   • Data Provenance: The data was collected from two prospective clinical trial sites in the United States: University of Texas Medical Branch, Galveston, Texas and San Francisco General Hospital, San Francisco, California.
     • Initial specimens included 223 prenatal specimens from Clinical Site 1 and 225 random hospital specimens from Clinical Site 2.
     • These were augmented by an additional 75 supplemental masked serum specimens at each site to increase the number of positives.
     • Some specimens were frozen prior to analysis (110/298 at Site 1, 117/300 at Site 2), while unfrozen specimens were fresh or stored at 2-8°C for less than 1 week.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:

   • The primary "ground truth" for the comparative study was the Abbott IMx Toxoplasma IgG assay.
   • For discrepant samples, an Indirect Fluorescent Antibody (IFA) analysis was performed to resolve results.
   • The document does not specify the number of experts who performed the IFA testing or their specific qualifications (e.g., "Radiologist with 10 years of experience"). It only states that IFA discrepant sample testing was done by BBI - North American Clinical Laboratories in New Britain, CT using Gull Laboratories Toxo IgG Indirect Fluorescent Antibody Test.

4. Adjudication Method for the Test Set:

   • For the main comparative study with Abbott IMx, discrepant samples at clinical site 2 were subsequently tested twice on both instruments (IMMUNO 1 and IMx) and classified as either positive or negative based on "two out of three results". This implies a form of consensus, where if the two re-tests agreed, that settled the classification.
   • Furthermore, IFA analysis was used for resolution if there was a discrepancy between the IMMUNO 1 and IMx results. "Resolution by IFA excludes a discrepant result if agreement between IFA and Immuno 1 is found." This suggests a hierarchical adjudication: first IMx comparison, then re-testing, then IFA as a tie-breaker or gold standard for specific discrepancies.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:

   • No, an MRMC comparative effectiveness study was not done. This study evaluates the performance of a diagnostic assay (an in-vitro diagnostic device), not a device involving human interpretation (like imaging or AI algorithms). Therefore, the concept of "human readers improve with AI vs without AI assistance" is not applicable here.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:

   • Yes, this is a standalone device performance study. The Technicon IMMUNO 1® Toxoplasma IgG method is an automated in vitro diagnostic assay. Its performance (quantitatively measuring Toxoplasma IgG) is assessed directly through laboratory testing, without human interpretation of images or other subjective inputs that would require a human-in-the-loop component. The results are quantitative IU/mL values.

7. The Type of Ground Truth Used:

   • The primary ground truth for the comparative study was the Abbott IMx Toxoplasma IgG assay, which is itself an FDA-cleared device for the same indication.
   • For resolving discrepancies, Indirect Fluorescent Antibody (IFA) analysis was used. IFA is a laboratory technique often considered a reference method for antibody detection, especially in toxoplasmosis serology.
   • Additionally, the device's calibration is traceable to the WHO anti-Toxoplasma Serum International Standard (TOXS-60), which serves as a recognized reference standard for quantifying Toxoplasma IgG.

8. The Sample Size for the Training Set:

   • This document describes a clinical validation study for a new assay, not an AI or machine learning algorithm. Therefore, the concept of a "training set" in the context of machine learning is not applicable. The device is an instrument and reagent system that measures IgG levels based on established biochemical principles, not learned patterns from data.

9. How the Ground Truth for the Training Set was Established:

   • As noted above, a "training set" is not relevant for this type of IVD device. The assay's "calibration" is established using a set of six calibrators (0, 10, 20, 50, 100, 300 IU/mL) that are traceable to the WHO anti-Toxoplasma Serum International Standard (TOXS-60). This standard itself is the "ground truth" for quantitative accuracy.

Regulation Number and Section

§ 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).