(59 days)
This in vitro diagnostic procedure is intended to quantitatively measure CRP in human serum on the Cobas Mira chemistry analyzer . Such measurements are used in the diagnosis and treatment of bacterial infections and inflammation.
Are reagent systems for the quantitation of the concentration of CRP in human serum. Are based on the agglutination of CRP in serum with latex particles coated with anti-CRP. Employ the absorbance change observed as the basis for quantitation. Are intended for use with the Cobas Mira chemistry analyzer.
Here's an analysis of the provided text regarding the acceptance criteria and study for the CRP-LATEX "SEIKEN" XR device:
Acceptance Criteria and Device Performance Study
The submission focuses on establishing substantial equivalence to a predicate device (quantex CRP plus) rather than setting distinct acceptance criteria for the new device as a standalone product. The performance characteristics of the CRP-LATEX "SEIKEN" XR are presented in comparison to the predicate device, demonstrating similarity in key areas.
1. Table of Acceptance Criteria and Reported Device Performance
The concept of "acceptance criteria" here is primarily demonstrated by showing that the CRP-LATEX "SEIKEN" XR performs similarly to or better than the predicate device for several metrics. The table below compiles the directly comparable performance characteristics.
| Performance Characteristic | Acceptance Criteria (Implied by Predicate) | CRP-LATEX "SEIKEN" XR Performance |
|---|---|---|
| Min. Detectable Conc. | 0.3 mg/dl | 0.1 mg/dl |
| Precision (Between-run CV) | Less than 10% | 1.94%, 2.24%, 1.58% |
| Linearity Range | 0.3 - 10.0 mg/dl | 0.1 - 20.0 mg/dl |
| Correlation (vs. Predicate) | Strong correlation expected (r ≈ 1) | r = 0.9976 (y = 0.005 + 1.126X) |
Note: The submission aims to show "substantial equivalence" rather than predefined numerical acceptance criteria specific to the new device itself. The "acceptance criteria" here are implied by the existing performance of the cleared predicate device. For precision, the "less than 10%" is likely a general industry or internal acceptance for CV, and the new device performs well within this.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set:
- Accuracy/Correlation: 122 serum samples.
- Within-run Precision: 10 replicates for each of 5 levels of control serum.
- Between-run Precision: 1 sample ("commercial control serum") analyzed once per day for 10 days for 3 levels (Sample 1, Sample 2, Sample 3).
- Linearity: A series of 12 calibrators for each of 3 separate lot numbers of reagents.
- Stability: 3 levels of commercial control serum analyzed at 3-month intervals over the shelf life for 2 lot numbers of reagents.
- Data Provenance: The data was prepared at and is on file at Denka Seiken Co., Inc. This suggests the data was generated internally by the manufacturer. No specific country of origin for the samples (e.g., patient demographics, serum source) is mentioned, nor is it specified if the studies were retrospective or prospective, though clinical diagnostic device performance studies are generally considered prospective assessments of the device under controlled conditions.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
N/A. This is an in-vitro diagnostic (IVD) device for quantitative measurement of C-Reactive Protein (CRP) in human serum. The "ground truth" for IVD devices is typically established through reference methods, calibrated standards, or comparative testing against another established assay (the predicate in this case) rather than expert interpretation of images or other subjective assessments. Therefore, "expert qualifications" in the sense of medical image interpretation are not applicable here. The "experts" would be laboratory scientists and technicians following established protocols.
4. Adjudication Method for the Test Set
N/A. Adjudication methods like 2+1 or 3+1 are typically used in studies where human readers interpret data (e.g., medical images) and their interpretations need to be reconciled to establish a consensus ground truth. For this IVD device, the measurements are quantitative and objective, so no such adjudication process is needed for the outputs of the device or the predicate.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No. An MRMC study is not applicable. This is an in-vitro diagnostic device, not a device requiring human reader interpretation (e.g., an AI-assisted imaging device). The comparison is between two quantitative assays.
6. Standalone Performance (Algorithm only without Human-in-the-loop)
Yes, the study presents standalone performance of the CRP-LATEX "SEIKEN" XR. This device is an automated reagent system for a chemistry analyzer. Its performance metrics (precision, linearity, accuracy/correlation) are intrinsic to the assay and the analyzer's measurement capabilities, operating without human interpretive input altering the result. The device itself is the "algorithm" and it functions entirely on its own to produce a quantitative result.
7. The Type of Ground Truth Used
The "ground truth" for the test set is established by:
- Comparison to a Predicate Device: For accuracy, the CRP-LATEX "SEIKEN" XR results were correlated against the results obtained from the predicate device, quantex CRP plus. This establishes the predicate device's measurements as the reference for comparison.
- Commercial Control Sera/Calibrators: For precision and linearity, commercial control sera and calibrators with known or expected values were used. These are typically manufactured to precise specifications with assigned values.
8. The Sample Size for the Training Set
N/A. This documentation describes a conventional IVD reagent system, not a machine learning or AI-driven device that requires a "training set" in the context of algorithm development. The "training" for such a system involves calibrating the assay and establishing its performance characteristics, not iteratively training a predictive model.
9. How the Ground Truth for the Training Set Was Established
N/A. As mentioned above, there is no "training set" in the sense of data used to develop a machine learning model. The ground truth for calibrators and control materials used in the development and ongoing use of the assay would typically be established through an unbroken chain of traceability to reference materials and/or international reference methods.
§ 866.5270 C-reactive protein immunological test system.
(a)
Identification. A C-reactive protein immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the C-reactive protein in serum and other body fluids. Measurement of C-reactive protein aids in evaluation of the amount of injury to body tissues.(b)
Classification. Class II (performance standards).