(801 days)
Hemosure® Accu-Reader™ A100 is an automated immunochemical fecal occult blood test system intended for the qualitative detection of fecal occult blood in human feces by clinical laboratories.
Hemosure® Accu-Reader™ A100 is comprised of Hemosure® Accu-Reader™ A100 Reader with Sample Tray, Hemosure Accu-Reader™ A100 Test Cartridge, Sample Collection tube, Hemosure® Accu-Reader™ A100 Control and Hemosure® Accu-Reader™ A100 Calibration Cartridge Kit.
For in vitro diagnostic use. For Prescription use.
Hemosure® Accu-Reader™ A100 is an automated immunochemical fecal occult blood test system intended for the qualitative detection of fecal occult blood in human feces by clinical laboratories. Hemosure® Accu-Reader™ A100 is comprised of Hemosure® Accu-Reader™ A100 Reader with Sample Tray, Hemosure Accu-Reader™ A100 Test Cartridge, Sample Collection tube, Hemosure® Accu-Reader™ A100 Control and Hemosure® Accu-Reader™ A100 Calibration Cartridge Kit.
The principle of measurement is an automated sandwich dye conjugate immunoassay that employs a combination of monoclonal antibodies to selectively identify and provide qualitative determination of human hemoglobin in feces. As the test sample flows up through the absorbent device, the labeled antibody-dye conjugate binds to the hemoglobin in the specimen, forming an antibody-antigen complex. This complex binds to anti-hemoglobin antibody in the positive test reaction zone and produces a pink-rose color band. In the absence of hemoglobin, there is no line in the positive test reaction zone. The pink-rose color bands in the control reaction zone demonstrate that the reagents and devices are functioning correctly.
The throughput of the instrument is 100 samples are collected in the sample collection tube "Sample Collection tube". The sample tube and test cartridge are assembled and placed on the sample tray. The instrument positions the plunger station to initiate the test cartridge testing by plunging the sample collection buffer tube into the chamber of the cartridge and thereby piercing its aluminum seal. The test fecal sample buffer is released into the test cartridge and fecal sample buffer will migrate on the enclosed test strip affixed on the test cartridge. Results are read after the tray makes one full rotation, which takes 5 minutes. Immediately after sample reading, the result (positive, negative or invalid) is displayed on the touchscreen and printed on paper whose dispensing slot is situated at the top of the Accu-Reader™ A100.
Here's an analysis of the acceptance criteria and study detailed in the provided document for the Hemosure Accu-Reader A100 device:
Acceptance Criteria and Reported Device Performance
1. Table of Acceptance Criteria and Reported Device Performance:
The document doesn't explicitly state a single, overarching acceptance criterion as a numerical threshold (e.g., "accuracy > 95%"). Instead, it demonstrates acceptable performance across various studies (precision, cross-reactivity, interference, stability, clinical performance) by consistently achieving high levels of "agreement" and confirming expected results. The primary measure used to show effectiveness, particularly in the clinical method comparison, is the "Overall Percent Agreement (OPA)," "Positive Percent Agreement (PPA)," and "Negative Percent Agreement (NPA)" with a predicate device.
| Performance Characteristic | Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|---|
| Precision/Reproducibility | High Positive Percentage Agreement (PPA) and Negative Percentage Agreement (NPA) across different conditions (intra-assay, inter-site, between-run, between-instrument, lot-to-lot). Consistent expected results for various hemoglobin concentrations. | Intra-Assay: PPA 98.86%, NPA 98.31% |
| Between-run: OPA 99.09%, PPA 99.25%, NPA 98.84% | ||
| Between-Instrument: OPA 99.09%, PPA 99.25%, NPA 98.86% | ||
| Lot-to-Lot: OPA 99.32%, PPA 99.63%, NPA 98.84% | ||
| Between-site: OPA 99.32%, PPA 99.44%, NPA 99.13% | ||
| All concentrations showed expected positive/negative trends with high agreement. | ||
| Assay Cut-off Performance | Overall percent agreement of more than 95% with predicate device at the analytical cut-off. | Overall percent agreement > 95% with predicate device. |
| Prozone (Hook) Effect | No false negatives at high concentrations up to 3000 ng/mL. | No false negatives up to 3000 ng/mL. |
| Analytic Sensitivity (hHb variant) | Ability to detect human hemoglobin-S variant. | Found to be sensitive to Hb-S variant at various concentrations (e.g., 95% positive at 120 ng/mL, 100% positive at 140 ng/mL). |
| Cross-Reactivity (Animal Hemoglobin) | No significant cross-reactivity with common animal hemoglobin (ovine, poultry, fish, horse, goat, pig, rabbit, sheep). | No significant cross-reactivity observed, with high OPA, PPA, and NPA for all tested animal hemoglobins (e.g., OPA > 98% in all cases). |
| Interfering Substances | No significant interference from meat extracts, dietary substances, vegetable extracts, toilet water, and contaminants. | No significant interference observed for all tested substances, with high OPA, PPA, and NPA typically above 95%. |
| Sample Collection | High degree of accuracy of results and consistency of stool collected by laypersons. | Demonstrated high accuracy and consistency (specific quantitative metrics not provided but implied as acceptable). |
| Specimen Stability | Samples remain stable and device accuracy maintained over specified storage conditions and durations. | Agreement over 95% for samples stored at 2-8°C, -10-(-)20°C, 30°C for up to 30 days. Noted false negatives at 40°C after 15 days, leading to specific storage guidance (no more than 14 days at 30°C and 40°C). |
| Shipping Stability | Samples remain stable and device accuracy maintained after shipping stress under extreme temperatures. | Agreement over 95% for samples after shipping stress for up to 6 days at -10°C, 2-8°C, 25°C, and 40°C. |
| Accelerated Stability (Kit) | Support of a 24-month shelf life at room temperature. | Data supported 24-month shelf life at room temperature (based on 75 days at 45°C). |
| Real-Time Stability (Kit) | Test kits are stable up to 36 months when stored at 4-30°C. | Test kits stable for 24 months at 4-30°C (ongoing study for 36 months). |
| Clinical Performance | High overall, positive, and negative percent agreement with a legally marketed predicate device. | Overall: OPA 98.67% (96.93%-99.43%) |
| Positive: PPA 98.63% (93.51%-99.97%) | ||
| Negative: NPA 98.71% (96.87%-99.76%). Agreements are above 98%. | ||
| Cybersecurity | Data security vulnerability evaluated and risks mitigated. | Evaluation done, mitigations incorporated (details not provided). |
| EMC | Device meets international standards for electromagnetic compatibility. | Passed all specified IEC 61326-1 and IEC 60601-1-2 standards tests. |
2. Sample Size Used for the Test Set and Data Provenance:
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Clinical Performance Study:
- Sample Size: A total of 377 clinical fecal samples were used.
- Data Provenance: The samples were collected from individuals who had previously been screened by colonoscopy. The study was conducted at three different sites, indicating a likely prospective or retrospective multi-center clinical study setup, although the document does not definitively state "prospective" or "retrospective." The samples are human fecal samples. The country of origin is not explicitly stated.
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Other Studies (Precision, Cross-Reactivity, Interference, Stability, Analytic Sensitivity):
- The test set for each of these studies used 21 replicates for each concentration (spanning various hemoglobin levels, including negative controls, around the cut-off, and high positive).
- Data Provenance: These studies generally involved contrived or spiked samples (e.g., human hemoglobin, animal hemoglobin, interfering substances spiked into fecal samples). The provenance of the base fecal samples or the location of these analytical studies is not explicitly stated, but they are laboratory-based analytical studies rather than clinical field studies.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
-
For the Clinical Performance Study, the ground truth appears to be based on a legally marketed predicate device (OC-Auto Micro FOB Test) and "individuals who had previously been screened by colonoscopy." The document does not specify the number or qualifications of experts (e.g., radiologists, gastroenterologists, pathologists) who established the ground truth from the colonoscopy results. It's implied that the findings from the colonoscopy were used to determine the true positive/negative status for fecal occult blood, which was then compared to the device and predicate.
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For the Analytical Studies (Precision, Cross-Reactivity, Interference, Stability, Analytic Sensitivity), the "ground truth" for the test samples was established by preparing samples with known concentrations of human hemoglobin (or other substances). This is a controlled laboratory setting, so "experts" in the sense of clinical reviewers for ground truth are not applicable here. The known concentrations themselves served as the ground truth.
4. Adjudication Method for the Test Set:
- The document does not describe an explicit adjudication method for the clinical study test set in terms of human expert review. The comparison is made against a "predicate device" and implied "colonoscopy" results.
- For the analytical studies, the "ground truth" was established by the known concentrations of spiked analytes, so adjudication was not necessary.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done, and Effect Size:
- No, a standard MRMC comparative effectiveness study, where human readers interpret cases with and without AI assistance to measure improvement, was not conducted.
- This device, the Hemosure Accu-Reader A100, is an automated immunochemical fecal occult blood test system. It is designed for qualitative detection of fecal occult blood in human feces by clinical laboratories, with results read by a camera-based reader and displayed as "positive, negative or invalid." It is an in vitro diagnostic device, not an image interpretation AI system that assists human readers. Therefore, the concept of "human readers improve with AI vs without AI assistance" does not directly apply to this type of device.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done:
- Yes, this was a standalone performance study. The Hemosure Accu-Reader A100 is an automated system. Its "performance characteristics" (precision, analytical sensitivity, cross-reactivity, interference, stability, and clinical comparison to a predicate) reflect the algorithm's performance in analyzing the test cartridge without human intervention in the result interpretation. The reader (machine) identifies and provides qualitative determination of human hemoglobin.
7. The Type of Ground Truth Used:
- For the Clinical Performance Study: The ground truth was based on the performance of a predicate device (OC-Auto Micro FOB Test) and, implicitly, outcomes data from colonoscopy screenings.
- For Analytical Studies (Precision, Prozone, Analytic Sensitivity, Cross-Reactivity, Interfering Substances, Specimen and Shipping Stability, Accelerated and Real-Time Kit Stability): The ground truth was known concentrations of spiked human hemoglobin (or other substances like animal hemoglobin or interfering agents) in fecal samples. These are essentially controlled experimental conditions.
8. The Sample Size for the Training Set:
- The document does not provide information on a training set size. As an in vitro diagnostic device, this typically refers to a specific assay method and an automated reader. While the reader uses digital imaging to analyze lines, it's not described as a deep learning or traditional machine learning system requiring a large "training set" in the common sense for AI algorithms. The system's "training" would be more akin to calibration and optimization of its optical analysis and interpretation logic, rather than iterative learning from a large labeled dataset. The various analytical studies validate its performance but are not explicitly referred to as a "training set."
9. How the Ground Truth for the Training Set Was Established:
- Since a "training set" in the context of an AI algorithm is not explicitly mentioned or implied for this device, the method for establishing its ground truth is not applicable/not provided. The device relies on a pre-defined sandwich dye conjugate immunoassay principle and a calibrated optical system.
§ 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.