(26 days)
Tina-quant Cystatin Gen.2 is an in vitro test for the quantitative determination of cystatin C in human serum and plasma on Roche/Hitachi cobas c systems. Cystatin C measurements are used as an aid in the diagnosis and treatment of renal diseases.
The Roche Tina-quant Cystatin C Gen.2 assay provides quantitative measurement of the cystatin C that is present in human serum and plasma. The reagents are packaged in a cassette with two bottles labeled with their instrument positioning, R1 (Reagent 1) and R2 (Reagent 2).
R1 contains a solution of polymers in MOPS-buffered saline with preservative and stabilizers. R2 is latex particles coated with anti-cystatin C antibodies (rabbit) in glycine buffer with preservatives and stabilizers.
Human cystatin C agglutinates with the antibody coated latex particles. The aggregate is determined turbidimetrically.
The provided text describes a 510(k) premarket notification for a modified in vitro diagnostic device, "Tina-quant Cystatin C Gen.2". The modifications primarily involve updated labeling information rather than changes to the device itself. Therefore, the study details are focused on validating these labeling changes.
Here's an analysis based on the provided document:
1. A table of acceptance criteria and the reported device performance
| Feature/Metric | Acceptance Criteria (Predicate) | Reported Device Performance (Candidate) |
|---|---|---|
| Sample Stability | Not specified in provided text (new information added to labeling) | New room temperature and refrigerated serum and plasma sample stability information was added. Specific data not provided, but the process describes testing samples in triplicate at 15-25 °C and 2-8 °C, with results compared to time zero. The conclusion states "all of the acceptance criteria were met," implying satisfactory stability for the expanded claims. |
| High dose hook-effect | No false result occurs up to a cystatin C concentration of 20 mg/L. | No false result occurs up to a cystatin C concentration of 12 mg/L. (This is a more conservative and reduced claim compared to the predicate.) |
| HARA interference | Not specified in provided text (new warning added to labeling) | Warning added: "In very rare cases falsely elevated results for Cystatin C will be obtained from samples taken from patients who have been treated with rabbit antibodies or have developed anti-rabbit antibodies." This warning is supported by internal testing and cited literature, indicating the device exhibited interference in the presence of HARA, leading to the label change. |
| Intended use/Indications | Quantitative determination of cystatin C in human serum and plasma as an aid in diagnosis and treatment of renal diseases. | Same |
| Test principle | Particle enhanced immunoturbidimetric assay | Same |
| Instrument | Roche/Hitachi cobas c 501 | Same |
| Sample type | Serum, Li-heparin, K2-, and K3- EDTA plasma | Same |
| Measuring Range | 0.40 - 6.80 mg/L | Same |
| Precision | See predicate method sheet | Same |
| LoB | 0.30 mg/L | Same |
| LoD | 0.40 mg/L | Same |
| LoQ | 0.40 mg/L | Same |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Sample Stability: Human serum and plasma patient samples were adjusted with cystatin C. The exact number of samples is not explicitly stated, but it mentions "patient samples" and that "These samples are split into two sets". The text does not specify the country of origin or whether the data was retrospective or prospective, but it implies prospective testing for stability.
- High dose hook-effect: A human serum pool was used, from which an 18-step dilution series was prepared. The exact volume or number of individual samples within the pool is not specified. Data provenance is not given.
- HARA interference: "Internal testing was done at Roche to confirm the customer results." The number of samples tested internally and the provenance of customer data are not detailed.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
Not applicable. This device is an in vitro diagnostic (assay for a biomarker), not an imaging or diagnostic device requiring expert interpretation of results for ground truth. Ground truth for an assay is typically established through reference methods or spiked samples with known concentrations.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
Not applicable. Adjudication methods like 2+1 or 3+1 are typically used in clinical trials or studies where subjective interpretations (e.g., image readings) are being evaluated. For an IVD, the results are quantitative measures.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
Not applicable. This study is for a laboratory assay, not an AI-assisted diagnostic tool for human readers.
6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done
This refers to the performance of the analytical device itself. The studies described for sample stability, hook effect, and HARA interference were standalone evaluations of the assay's performance characteristics.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
- Sample Stability: The ground truth for sample stability was the result of the fresh sample at time zero, which is considered the baseline and implicitly the "true" concentration at that point.
- High dose hook-effect: The ground truth was the "known concentration" obtained from preparing a dilution series from a concentrated serum pool.
- HARA interference: The ground truth was based on confirming "falsely elevated results" observed in patient samples and corroborated by peer-reviewed literature.
8. The sample size for the training set
Not applicable. This device is an in vitro diagnostic reagent kit, not a machine learning or AI algorithm that requires a training set. The "training set" concept does not apply here.
9. How the ground truth for the training set was established
Not applicable, as there is no training set for this type of device.
§ 862.1225 Creatinine test system.
(a)
Identification. A creatinine test system is a device intended to measure creatinine levels in plasma and urine. Creatinine measurements are used in the diagnosis and treatment of renal diseases, in monitoring renal dialysis, and as a calculation basis for measuring other urine analytes.(b)
Classification. Class II.