Search Results

Premier Toxins A&B is a qualitative enzyme immunoassay for the detection of Clostridium difficile toxin A and toxin B in stool from patients with antibiotic associated diarrhea. Premier Toxins A&B is intended for use as an aid in diagnosis of C. difficile associated disease.

Premier Toxins A&B is an enzyme immunoassay for the direct detection of Clostridium difficile toxin A and toxin B in stool samples. Breakaway microwells are coated with toxin specific monoclonal and polyclonal antibodies. Diluted patient specimens and HRP-conjugated anti-toxin A and B polyclonal antibodies are added to microwells. If either toxin is present in the diluted patient samples, HRP-conjugated toxin polyclonal antibodies (specific for both toxins) complexes are formed which remain in the microwells after washing. After a final washing step, a substrate / chromagen (urea peroxide and tetramethylbenzidine) is added to the wells. Any bound conjugate converts the substrate / chromagen to a blue color. Addition of acid (Stop Solution) converts the blue to a vellow color.

Here's an analysis of the provided text regarding the acceptance criteria and study for the Premier Toxins A&B device:

The document does not explicitly state pre-defined "acceptance criteria" in terms of specific performance thresholds that the device needed to meet. Instead, it presents the results of a clinical study, implying that these results were considered acceptable for 510(k) clearance by demonstrating substantial equivalence to a predicate device.

1. Table of Acceptance Criteria and Reported Device Performance

As noted, explicit "acceptance criteria" were not listed. However, we can construct a table showing the reported performance statistics from the clinical study. These reported values served as the evidence for substantial equivalence.

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

• Sample Size (Test Set):
  • Cytotoxin Positive: 90 (Site 1: 55, Site 2: 35)
  • Cytotoxin Negative: 465 (Site 1: 257, Site 2: 208)
  • Total Samples (All Sites): 90 + 465 = 555
• Data Provenance:
  • Country of Origin: United States (stated as "performed at two sites in the United States").
  • Retrospective or Prospective: Not explicitly stated, but typically for clinical studies supporting 510(k) in vitro diagnostics, especially for comparison to standard methods, samples might be collected prospectively, or a mix of archived and prospective samples. The document does not provide enough detail to definitively classify it.

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

• Ground Truth Method: The ground truth was established by comparison to the "cellular cytotoxicity assay." This is a laboratory-based method, not an expert review of images or clinical data in the human-reader sense.
• Number of Experts: Not applicable, as the ground truth was determined by a laboratory assay, not human experts.
• Qualifications of Experts: Not applicable.

4. Adjudication Method for the Test Set

• Adjudication Method: Not applicable. The "ground truth" was a laboratory reference method (cellular cytotoxicity assay), which has its own established interpretation criteria, not subject to human adjudication in the typical sense of reconciling multiple human readers.

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

• MRMC Study: No, an MRMC comparative effectiveness study was not conducted. This study compares the device directly to a laboratory reference method (cellular cytotoxicity assay) using stool samples, not a comparison of human readers with and without AI assistance.

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

• Standalone Performance: Yes, this study effectively represents standalone performance. The Premier Toxins A&B device (an enzyme immunoassay) is an automated algorithm-only system in the sense that the test results (color change, absorbance readings) are interpreted by the device's inherent mechanisms to produce a positive or negative result, without direct human intervention in the interpretation of the test itself. The performance statistics (sensitivity, specificity, etc.) are for the device's output compared to the reference standard.

7. The Type of Ground Truth Used

• Type of Ground Truth: The ground truth used was a laboratory reference standard: the cellular cytotoxicity assay. This is a well-established method for detecting Clostridium difficile toxins.

8. The Sample Size for the Training Set

• The document does not provide any information regarding a "training set" or its sample size. This is common for older 510(k) submissions for in vitro diagnostic devices like ELISAs, which are developed and validated using traditional laboratory methods. The concept of a distinct "training set" and "test set" in the machine learning sense is not explicitly applied here. The clinical study described served as the validation (test) set.

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

• Not applicable, as no information on a distinct "training set" is provided.

In summary: The Premier Toxins A&B device demonstrated strong performance (high sensitivity, specificity, and negative predictive value) when compared against the cellular cytotoxicity assay, which served as the gold standard. While explicit numerical acceptance criteria were not stated, the reported performance statistics were deemed sufficient by the FDA for clearance, supporting the device's intended use as an aid in diagnosing C. difficile-associated disease. The study was a standalone validation of the device against a laboratory reference method, not an AI-assisted human reader study.

Ask a specific question about this device