(224 days)
The FOB One Step Rapid Test is a rapid chromatographic immunoassay for the qualitative detection of human occult blood in human fecal specimens. The device is suitable for use in laboratories and physician's offices as well as for Over the Counter Use.
The FOB One Step Rapid Test is a lateral flow chromatographic immunoassay based on the principle of the double antibody-sandwich technique. The membrane is pre-coated with anti-hemoglobin antibody on the test line region of the device. During testing, the specimen reacts with the particle coated with anti-hemoglobin antibody. The mixture migrates upward on the membrane chromatographically by capillary action to react with anti-hemoglobin antibody on the membrane and generate a colored line. The presence of this colored line in the test region indicates a positive result, while its absence indicates a negative result. To serve as a procedural control, a colored line will always appear in the control line region indicating that proper volume of specimen has been added and membrane wicking has occurred.
Here's an analysis of the provided text, focusing on the acceptance criteria and study details for the Orient Gene Biotech - One Step Rapid FOB device:
1. Table of Acceptance Criteria and Reported Device Performance
Based on the provided text, the acceptance criteria are not explicitly stated as clear, pre-defined thresholds. Instead, the study aims to demonstrate performance that is comparable to, or meets expected results. I've inferred the expected performance based on the wording.
| Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|
| Detection Limit (Sensitivity): Expected to detect 50 ng hHb/mL and higher. | 50 ng hHb/mL: 100% positive (20/20 samples) |
| 62.5 ng hHb/mL: 100% positive (20/20 samples) | |
| 2000 ng hHb/mL: 100% positive (20/20 samples) | |
| 0 ng hHb/mL: 0% positive (0/20 samples) | |
| 37.5 ng hHb/mL: 0% positive (0/20 samples) | |
| No Pro-zone Effect: No false negatives at high concentrations. | No pro-zone effect seen up to 2000 ng hHb/ml. |
| Inter-Site Reproducibility: Consistent results across different sites and lots. | All 45 samples for 50, 62.5, and 2000 ng/mL hHb concentrations were positive across 3 sites and 3 lots. All 45 samples for 0 and 37.5 ng/mL hHb concentrations were negative. |
| Intra-Run Reproducibility: Consistent results within a single run. | All 30 samples for 50, 62.5, and 2000 ng/mL hHb concentrations were positive across 3 lots. All 30 samples for 0 and 37.5 ng/mL hHb concentrations were negative. |
| Inter-Day Reproducibility: Consistent results across different days. | All 30 samples for 50, 62.5, and 2000 ng/mL hHb concentrations were positive across 3 days. All 30 samples for 0 and 37.5 ng/mL hHb concentrations were negative. |
| Accuracy (Technical Personnel): High agreement with expected and predicate device results. | 99.0% agreement with expected results (for 3 sites). 98.0% agreement with predicate device results (for 3 sites). |
| Accuracy (Non-Technical Personnel - Layuser): High agreement with expected and predicate device results. | 98.7% agreement with expected results (Orient Gene FOB Test Layuser vs. Expected). 98.0% agreement with predicate device results (Orient Gene FOB Test Layuser vs. Predicate test). |
| Percent Positive Agreement (Technical Personnel vs. Predicate): High agreement for positive samples. | 98.3% (95% C.I. = 91.1% - 100%) |
| Percent Negative Agreement (Technical Personnel vs. Predicate): High agreement for negative samples. | 97.5% (95% C.I. = 86.8% - 99.9%) |
| Overall Agreement (Technical Personnel vs. Predicate): High overall agreement. | 98.0% (95% C.I. = 93.0% - 99.8%) |
| Potential Interferences: No significant interference from tested substances. | Interference study carried out, no adverse results explicitly stated, implying no significant interference. |
| Potential Cross Reactors: No false positives from animal hemoglobin. | No reaction from various animal hemoglobins at 200 ng/mL. |
2. Sample Size Used for the Test Set and Data Provenance
- Detection Limit: 100 hemoglobin-free stool samples were used, spiked with varying concentrations (divided into groups of 20 for each concentration level). Data provenance is not specified (e.g., country of origin), but it appears to be lab-based, likely retrospective as samples were spiked.
- Potential Interferences: Not specified, but involved aqueous fecal samples. Likely retrospective (lab-prepared).
- Potential Cross Reactors: Not specified, but involved negative and positive fecal samples spiked with animal hemoglobin. Likely retrospective (lab-prepared).
- Reproducibility (Inter-Site): 75 hemoglobin-free fecal samples (split into groups for each concentration, 15 per group, tested 5 times each lot).
- Reproducibility (Intra-Run): 50 hemoglobin-free fecal samples (split into groups, 10 per group, tested 10 times each).
- Reproducibility (Inter-Day): 50 fecal samples (split into groups, 10 per group, tested 10 replicates each day for 3 days).
- Accuracy (Technical Personnel): 100 human stool extraction samples (20 replicates at each concentration). Data provenance is not specified, but the study was conducted at "three physician office laboratories." This suggests prospective collection or preparation of samples for this specific study.
- Accuracy (Non-Technical Personnel): 150 human stool extraction samples (30 at each concentration). Data provenance is not specified, but the study was conducted in a "medical laboratory." This also suggests prospective collection or preparation for the study.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
- For the Detection Limit, Reproducibility, Interference, and Cross-Reactivity studies, the ground truth was established by spiking known concentrations of human hemoglobin (or other substances) into hemoglobin-free fecal samples. This means the known concentration of the analyte served as the ground truth. No human experts were explicitly stated to establish this ground truth, as it was a controlled, experimental setup.
- For the Accuracy studies, the "expected results" for the spiked samples also served as a ground truth (i.e., whether the spiked concentration should result in a positive or negative test). Additionally, the predicate device was used as a comparative "ground truth" or reference standard. No specific number or qualifications of experts are given for establishing the "expected results" for spiked samples, as these are inherent to the experimental design.
4. Adjudication Method for the Test Set
Not applicable. The ground truth for most studies was established by the known concentrations of spiked analytes. For the accuracy study, comparisons were made against "expected results" (based on spiking) and the predicate device. There was no mention of an adjudication process by multiple human observers to establish a consensus ground truth.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done in the traditional sense of evaluating human readers' diagnostic accuracy with and without AI assistance. This device is a rapid diagnostic test kit, not an AI imaging or diagnostic algorithm.
The "Accuracy" section does compare the new device's performance when used by both "technical personnel" and "non-technical personnel" (layusers) against the predicate device. This is a form of comparative effectiveness, but it's evaluating the device itself and its usability by different user groups, rather than the effect of AI assistance on human reader performance.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, the device itself, being a rapid diagnostic test, operates in a standalone manner. The results are interpreted visually (presence or absence of a colored line). While human users read the result, the "performance characteristics" (detection limit, reproducibility, interference, cross-reactivity) are essentially standalone performance evaluations of the device's ability to react to specific analyte concentrations. The "Accuracy" studies then evaluate human interpretation of these standalone device results.
7. The Type of Ground Truth Used
The primary type of ground truth used was known concentrations of spiked human hemoglobin (hHb) in hemoglobin-free fecal samples. This is a form of analytically defined ground truth or experimental ground truth. For the accuracy studies, the predicate device's results also served as a comparative ground truth.
8. The Sample Size for the Training Set
Not applicable. This device is a rapid chromatographic immunoassay, not an AI or machine learning algorithm that requires a "training set" in the computational sense. The device's components (antibodies, membrane, etc.) are manufactured based on established biochemical principles and quality control, not trained on data.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as there is no "training set" for this type of device.
§ 864.6550 Occult blood test.
(a)
Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood is blood present in such small quantities that it can be detected only by chemical tests of suspected material, or by microscopic or spectroscopic examination.)(b)
Classification. Class II (special controls). A control intended for use with an occult blood test is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 864.9.