(88 days)
The LIAISON® Helicobacter Antigen assay is a chemiluminescent immunoassay (CLIA) intended for the qualitative determination of Helicobacter pylori (H. pylori) antigen in human stool. The test is an aid in the diagnosis of patients suspected of H. pylori infection and to measure post therapy response from patients who have discontinued therapy for at least 4 weeks. Assay results should be used in conjunction with other clinical and laboratory data to assist the clinician in making individual patient management decisions.
The test must be performed on the LIAISON® XL Analyzer.
The LIAISON® Helicobacter Antigen Control Set is intended for use as assayed quality control samples to monitor the performance of the LIAISON® Helicobacter Antigen assay.
The performance characteristics of the LIAISON® Helicobacter Antigen Control Set have not been established for any other assay or instrument platforms different from the LIAISON® XL.
The LIAISON® Helicobacter Antigen assay is a delayed one-step sandwich assay for detection of H. pylori stool antigen. H. pylori antigen is first extracted from human stool samples with sample diluent using the LIAISON® Stool Extraction Device.
The assay uses a monoclonal antibody for detection of H. pylori stool antigen. The assay uses 200 µL of sample consisting of a mixture of extraction buffer and stool extracted H. pylori stool antigen which is incubated with paramagnetic particles coated with a capture antibody for H. pylori stool antigen. Following incubation, an isoluminol conjugated antibody for H. pylori stool antigen is added to the reaction and incubated. After the second incubation, the unbound material is removed with a wash cycle. The starter reagents are then added and a flash chemiluminescent reaction is initiated. The light signal is measured by a photomultiplier as relative light units (RLU) and is proportional to the concentration of H. pylori stool antigen present in the calibrators, controls or samples.
All assay steps and incubations are performed by the LIAISON® XL Analyzer.
Here's an analysis of the provided text, focusing on the acceptance criteria and the study details:
Device Name: LIAISON® Helicobacter Antigen
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined acceptance criteria in terms of numerical thresholds for sensitivity and specificity. Instead, it presents the achieved performance in clinical studies. We can infer the "accepted performance" to be the results obtained in these studies, which are then deemed sufficient for substantial equivalence.
| Metric | Acceptance Criteria (Implied) | Reported Device Performance (Pre-Therapy Population) | Reported Device Performance (Post-Therapy Population) |
|---|---|---|---|
| Clinical Specificity | Not explicitly stated | 98.6% (95.9 – 99.7% CI) | N/A (no 'not infected' cases in post-therapy study) |
| Clinical Sensitivity | Not explicitly stated | 95.5% (87.5 – 99.1% CI) | 100% (63.1 - 100% CI) |
Further Performance Data (Precision/Reproducibility):
The precision studies (12-Day and 5-Day) show low percent coefficients of variation (%CV) for various samples and controls, indicating good reproducibility. This data supports the reliability of the device but doesn't have a direct "acceptance criteria" table in the manner of specificity/sensitivity.
2. Sample Size Used for the Test Set and Data Provenance
- Pre-Therapy Population Test Set: 277 subjects (specimens)
- Post-Therapy Population Test Set: 8 subjects (specimens)
- Data Provenance:
- Country of Origin: Both within the US and outside the US (OUS). The specific countries OUS are not detailed.
- Retrospective or Prospective: Prospective study. Samples were collected from subjects undergoing evaluation for H. pylori infection.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The ground truth was established using a "Composite Reference Method (CRM)" which comprised at least two of the three methods:
- Histological Evaluation
- Culture of the Organism
- Urease Detection Test
The document does not specify:
- The number of experts involved in performing or interpreting these CRM methods.
- The qualifications of those experts (e.g., specific medical specialization, years of experience).
4. Adjudication Method for the Test Set
The document describes the ground truth as a "Composite Reference Method (CRM)" using at least two of three methods. It does not explicitly detail an adjudication method (e.g., 2+1, 3+1 consensus) if there were discrepancies between the CRM components. It implies that the CRM itself served as the definitive diagnosis.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size of AI Improvement
No, an MRMC comparative effectiveness study involving human readers and AI assistance was not performed. This device is an in-vitro diagnostic (IVD) assay designed for standalone performance, not for aiding human interpretation of complex images or data in an MRMC setting.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study Was Done
Yes, the clinical performance study directly assesses the standalone performance of the LIAISON® Helicobacter Antigen assay. The results (sensitivity and specificity) are for the device itself, against the Composite Reference Method, without human interpretation as a variable or as an aid to the device. The device is a "chemiluminescent immunoassay (CLIA)" performed on an automated analyzer (LIAISON® XL Analyzer).
7. The Type of Ground Truth Used
The ground truth used was a Composite Reference Method (CRM), consisting of at least two of the following:
- Histological Evaluation
- Culture of the Organism
- Urease Detection Test
This is a robust method often used in IVD studies to establish infection status. It directly assesses the presence of the pathogen by different laboratory techniques.
8. The Sample Size for the Training Set
The document does not mention a specific training set size or methodology. Given that this is an IVD assay, the development process would involve internal optimization and validation, but the reported performance data focuses on a distinct test set (prospective clinical study) to demonstrate performance against a reference standard. There isn't an "algorithm training set" in the sense of AI/machine learning models that typically require large, curated training datasets for model development.
9. How the Ground Truth for the Training Set Was Established
As no specific "training set" with separate ground truth establishment is described for an algorithm, this question is not directly applicable in the context of this device's submission. The development and internal validation of the assay (e.g., establishing optimal antibody concentrations, reaction times, cutoff values) would have occurred prior to the clinical performance studies, likely using characterized samples, but details of this are not part of the regulatory submission description for a training set.
§ 866.3110
Campylobacter fetus serological reagents.(a)
Identification. Campylobacter fetus serological reagents are devices that consist of antisera conjugated with a fluorescent dye used to identifyCampylobacter fetus from clinical specimens or cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by this bacterium and provides epidemiological information on these diseases.Campylobacter fetus is a frequent cause of abortion in sheep and cattle and is sometimes responsible for endocarditis (inflammation of certain membranes of the heart) and enteritis (inflammation of the intestines) in humans.(b)
Classification. Class I (general controls).