(172 days)
Gentian Cystatin C Immunoassay is an in-vitro diagnostic test for quantitative determination of cystatin c in human serum and plasma. The measurement of cystatin c is used in the diagnosis and treatment of renal diseases.
The Gentian cystatin C immunoassay is a particle enhanced turbidimetric immunoassay (PETIA). The immunoparticles are made from activated polystyrene microspheres to which avian anti-human cystatin C antibodies are covalently attached. The immunoparticles and cystatin C form aggregations that change the absorbance signal, depending on the amount of cystatin C present. Measurements obtained by this device are used for the determination of Cystatin C in human serum and plasma. The Gentian C assay is calibrated with human Cystatin C calibrators. Cystatin C controls are assayed for the verification of the accuracy and precision of the Gentian cystatin C immunoassay.
Here's a summary of the acceptance criteria and the study details for the Gentian Cystatin C Immunoassay, based on the provided text:
Acceptance Criteria and Device Performance
The core of the study is a comparison to a predicate device, the Dade Behring, Inc., N Latex Cystatin C Test Kit (K003503), rather than explicit numerical acceptance criteria for accuracy or precision. The primary acceptance criteria appear to be substantial equivalence, demonstrated by:
- Acceptable correlation statistics (Slope, Intercept, R-value) when compared to the predicate device across different instruments.
- Demonstration of comparable performance characteristics such as measuring range, linearity, precision, and interference.
| Acceptance Criteria (Implied for Substantial Equivalence) | Reported Device Performance (Gentian Cystatin C Immunoassay vs. Predicate) |
|---|---|
| Method Comparison Regression Analysis: | |
| Slope close to 1.0 | Study 1: |
| Modular P vs. BNII: 1.075 | |
| Modular P vs. BN ProSpec: 1.048 | |
| Study 2: | |
| Modular P vs. BN ProSpec: 1.021 | |
| Architect vs. BN ProSpec: 0.975 | |
| Intercept close to 0.0 | Study 1: |
| Modular P vs. BNII: 0.009 | |
| Modular P vs. BN ProSpec: 0.059 | |
| Study 2: | |
| Modular P vs. BN ProSpec: -0.025 | |
| Architect vs. BN ProSpec: -0.059 | |
| R-value close to 1.0 | Study 1: |
| Modular P vs. BNII: 0.986 | |
| Modular P vs. BN ProSpec: 0.992 | |
| Study 2: | |
| Modular P vs. BN ProSpec: 1.00 | |
| Architect vs. BN ProSpec: 0.989 | |
| Measuring Range: | 0.3 - 8.0 mg/L |
| Linearity: | 0.34 - 8.4 mg/L (Modular P), 0.27 - 8.8 mg/L (Architect) |
| Total Imprecision CV: | 4.2% (over 20 days with two lots) |
| Interference: | No significant interference from drugs, anticoagulants, hemoglobin (8 g/L), intralipid (11 g/L), triglycerides (14 g/L), bilirubin (420 mg/L). No RF interference. |
| Recovery: | 99-110% |
| Antigen Hook Effect: | Not significant below 16 mg/L (patient samples not expected to exceed 9 mg/L) |
| Sample Stability: | Up to one month at 2-8°C |
| Reagent Stability: | At least 18 months (reagents at 2-8°C), minimum 4 weeks (reagents in use) |
| Limit of Detection (LoD) & Limit of Quantitation (LoQ): | Within acceptance criteria and below lowest calibrator concentration. |
Study Information
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Sample Size used for the test set and the data provenance:
- Study 1: 172 (Modular P vs. BNII), 174 (Modular P vs. BN ProSpec)
- Study 2: 76 (Modular P vs. BN ProSpec), 87 (Architect vs. BN ProSpec)
- Total N for method comparison: 172 + 174 + 76 + 87 = 509 samples.
- Data Provenance: Not explicitly stated, but clinical studies are generally implied to be from human blood samples. No country of origin is mentioned, nor whether samples were retrospective or prospective.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Not applicable. This is an in-vitro diagnostic (IVD) device study comparing the performance of a new assay to a legally marketed predicate assay using patient samples. The "ground truth" here is the measurement from the established predicate device, not clinical expert consensus.
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Adjudication method for the test set:
- Not applicable for this type of IVD comparison study. The study involves quantitative measurements, not subjective evaluations requiring adjudication.
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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 is an IVD device for laboratory determination of a biomarker, not an imaging or diagnostic aid for human readers/clinicians, nor does it involve AI.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, this is effectively a standalone performance evaluation of the immunoassay system. It measures the device's ability to accurately quantify Cystatin C in samples.
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The type of ground truth used:
- The "ground truth" for the comparative studies was the results obtained from the predicate device, the Dade Behring, Inc., N Latex Cystatin C Test Kit (K003503). This is a common method for demonstrating substantial equivalence for new IVD assays. Other performance characteristics (linearity, precision, interference) are established against internal analytical standards.
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The sample size for the training set:
- The document does not explicitly mention a "training set" in the context of machine learning or algorithm development. For a turbidimetric immunoassay, the "training" equivalent would be the development and optimization of the assay reagents and conditions, as well as the calibration process with a set of known standards. The sample size for these development and calibration steps is not specified.
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How the ground truth for the training set was established:
- As above, the concept of a training set with "ground truth" established by experts doesn't directly apply here. The assay is calibrated using human Cystatin C calibrators. These calibrators would have known concentrations of Cystatin C, established through highly accurate reference methods (e.g., gravimetric preparation, reference laboratories, or certified reference materials).
§ 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.