(212 days)
The Astute Medical NEPHROCHECK® Test System is intended to be used in conjunction with clinical evaluation in patients who currently have or have had within the past 24 hours acute cardiovascular and or respiratory compromise and are ICU patients as an aid in the risk assessment for moderate or severe acute kidney injury (AKI) within 12 hours of patient assessment. The NEPHROCHECK® Test System is intended to be used in patients 21 years of age or older.
The Astute NEPHROCHECK® Test System is comprised of the NEPHROCHECK® Test Kit, the ASTUTE140® Meter Kit, NEPHROCHECK® Liquid Controls Kit and the NEPHROCHECK® Calibration Verification (Cal Vers) Kit. The system is designed to be used by trained medical professionals in the central laboratory. The NEPHROCHECK® Test Kit, includes the NEPHROCHECK® Test which is a single-use cartridge comprised of two immunoassays for the protein biomarkers, insulin-like growth factor-binding protein (IGFBP7) and tissue-inhibitor of metalloproteinases 2 (TIMP-2) on a membrane test strip enclosed in a plastic housing. The concentrations of the TIMP-2 and IGFBP-7 proteins are used to derive an AKIRISK™ Score. The test procedure involves the operator applying a clinical urine sample mixed with labeled fluorescent conjugate to the NEPHROCHECK® Test cartridge, and then inserting the Test cartridge into the ASTUTE140® Meter for incubation, reading, result calculation and result display. Internal positive and negative procedural controls in each NEPHROCHECK® Test cartridge monitor the function of each test cartridge. If the automatic check of these procedural controls shows that the control value results are not within pre-defined limits, the ASTUTE140® Meter will display an error message and the Test result will not be reported. Included in the NEPHROCHECK® Test is test buffer and the NEPHROCHECK® Test Conjugate Vial which contains murine monoclonal and goat polyclonal antibodies against TIMP-2 and IGFBP-7, fluorescent dye, stabilizers and excipients. Each Kit has the materials necessary to perform 25 tests. Each NEPHROCHECK® Test Kit also contains a lot-specific radio-frequency identification (RFID) card containing lot and calibration information. The RFID card information must be loaded prior to using a new Test kit lot. The AsTUTE140® Meter is a bench-top analyzer that converts the fluorescent signal from each of the two immunoassays (TIMP-2 and IGFBP7) contained within the NEPHROCHECK® Test cartridge into the AKIRISK™ Score. The NEPHROCHECK® Test result is displayed on the Meter LCD screen in approximately 20 minutes from the addition of the specimen. Only the AKIRISK™ Score appears on the Meter display. The AsTUTE140® Meter contains an internal printer that can print the AKIRisk score. The NEPHROCHECK® Low Liquid Control and NEPHROCHECK® High Liquid Control are bi-level, lyophilized control materials prepared from human urine containing human TIMP-2 and human IGFBP7 proteins with protein stabilizers. TIMP-2 and IGFBP-7 proteins have been added to the urine to achieve specified target concentration levels. Each NEPHROCHECK® Liquid Controls Kit also contains a high and low RFID encoded with the Liquid Control Kit lot number, expiration date, and the expected range of concentration values based on + two standard deviations in the measurement of each protein biomarker (TIMP-2 and IGFBP-7) in each Liquid Control level. Each NEPHROCHECK® Liquid Control Kit Vial is intended for single use only. The NEPHROCHECK® Calibration Verification Kit includes five levels of lyophilized material prepared from human urine, containing TIMP-2 and human IGFBP-7 to achieve specified target concentration levels that evenly span the reportable range of the AKIRISK™ Score. The expected concentrations and standard deviations of the individual biomarkers are printed on an enclosed Expected Values Card.
The provided text describes a Special 510(k) submission for modifications to the NEPHROCHECK® Test System. The document focuses on proving that these modifications do not raise new questions of safety or effectiveness and that the modified device remains substantially equivalent to the previously cleared predicate device.
Here's an analysis of the requested information based on the provided text:
1. A table of acceptance criteria and the reported device performance
The document does not explicitly present acceptance criteria in a table format alongside specific quantitative performance (e.g., sensitivity, specificity, accuracy) for the modified device in relation to diagnostic performance for AKI itself. Instead, it refers to various validation studies conducted to ensure the modifications do not negatively impact the device's original specifications. The overall acceptance criterion for this submission is that "The NEPHROCHECK® Test Kit met its specifications" and "No new risks were introduced by the minor modifications."
The studies performed and the implied performance criteria relate to maintaining the original device's integrity after the changes:
| Study | Standards Referenced | Reported Device Performance |
|---|---|---|
| NEPHROCHECK® Test Kit - Interfering Substances - Myoglobin | CLSI EP07-A2:2005, Interference Testing in Clinical Chemistry; Approved Guideline- 2nd Edition | Myoglobin was identified as a substance that does not exhibit interference with the AKIRisk™ Score. |
| NEPHROCHECK® Test Kit - Shelf-Life 2-8°C Storage and Ambient Shipping | CLSI EP25-A:2009 Evaluation of Stability of In Vitro Diagnostic Reagents; Approved Guideline; BS EN ISO 23640:2013 Stability testing of in vitro diagnostic reagent; ASTM D4332-13 Standard Practice for Conditioning Containers, Packages, or Packaging Components for Testing; ISTA 7E:2010 Testing Standard for Thermal Transport Packaging Used in Parcel Delivery System Shipment | The device maintained its performance specifications under the described storage and shipping conditions. |
| NEPHROCHECK® Test Kit – Buffer Open-Bottle Shelf-Life | (Same as Shelf-Life study) | The opened buffer maintained its performance specifications within its shelf-life. |
| NEPHROCHECK® Test Kit – Manufacturing and End-User Room Temperature Handling (Post 2-8°C Storage) | (Same as Shelf-Life study) | The device maintained its performance specifications after manufacturing and end-user handling at room temperature following refrigeration. |
| NEPHROCHECK® Test Kit – Effect of Cycling Between 2-8°C Storage and Room Temperature | EP07-A2:2005 Interference Testing in Clinical Chemistry; Approved Guideline- 2nd Edition. | The device maintained its performance specifications despite temperature cycling. |
| Time of the NEPHROCHECK® Test Cartridge to Reach Operating Temperature After 2-8°C Storage | EP07-A2:2005 Interference Testing in Clinical Chemistry; Approved Guideline- 2nd Edition. | The device reached operating temperature and maintained performance specifications within the intended timeframe. |
| NEPHROCHECK® Test Kit - Zero Equilibration Time Study | EP07-A2:2005 Interference Testing in Clinical Chemistry; Approved Guideline- 2nd Edition. | Performance specifications were met with zero equilibration time. |
| NEPHROCHECK® Test Kit - Packaging Material Environmental Cycling Study | ASTM D4332-13 Standard Practice for Conditioning Containers, Packages, or Packaging Components for Testing | Packaging maintained its integrity and protected the device as per specifications under environmental cycling. |
| Addition of a second supplier for anti-IGFBP-7 | CLSI EP17-A2, Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures; Approved Guideline—Second Edition | The anti-IGFBP-7 from the second supplier demonstrated equivalent detection capability and did not impact the AKIRisk™ Score. |
2. Sample size used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective)
The document lists various performance studies, but it does not specify the sample sizes used for these specific tests (e.g., number of samples for interference, shelf-life, or the second supplier validation).
The data provenance is not explicitly stated beyond referring to general industry standards (CLSI, ASTM, ISTA, BS EN ISO). Given that it's a modification to an existing device, these tests would likely involve laboratory-controlled experiments rather than patient data in the context of this specific submission. The original device's clearance (DEN130031/K131650) would have involved clinical studies, but this document pertains only to changes.
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)
This section is not applicable to the information provided in this document. The listed studies are technical performance tests (e.g., interference testing, stability testing, detection capability) conducted in a laboratory setting, not clinical studies requiring expert ground truth for patient diagnosis.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set
This section is not applicable as the document does not describe a clinical study involving human assessment or a ground truth process that would require adjudication.
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
This section is not applicable. The NEPHROCHECK® Test System is a diagnostic in-vitro device (an immunoassay system for biomarkers), not an AI-assisted imaging or diagnostic tool that involves human readers.
6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done
The NEPHROCHECK® Test System, as described, is a standalone diagnostic device in the sense that the ASTUTE140® Meter autonomously calculates and displays the AKIRISK™ Score based on the immunoassay results. While it's used "in conjunction with clinical evaluation" by medical professionals, the device itself performs the measurement and calculation without direct human input into the result generation process once the sample is applied and the test cartridge is inserted. The performance data presented here focuses on the stability and accuracy of this automated measurement system.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
For the specific performance studies described in this Special 510(k):
- Interference Testing: Ground truth is established by known concentrations of the interfering substance (myoglobin) and the expected stable measurement of the biomarkers (TIMP-2 and IGFBP-7) in its presence.
- Stability Studies: Ground truth is the initial performance specifications of the device when manufactured and tested under ideal conditions, against which performance after storage, handling, and cycling is compared.
- Second Supplier Validation: Ground truth involves comparing the detection capability of the antibody from the new supplier against the established performance of the original antibody or validated reference standards for TIMP-2 and IGFBP-7.
These are analytical performance ground truths, not clinical ground truths (like pathology or patient outcomes) related to the diagnosis of AKI, as this submission is for modifications, not original market clearance.
8. The sample size for the training set
The document does not mention a training set in the context of machine learning or AI. The NEPHROCHECK® Test System is an immunoassay system, not an AI or machine learning algorithm that requires a training set in that sense. The "AKIRISK™ Score" derivation would have been established and validated during the original device development (DEN130031/K131650), which might have involved statistical modeling but not a "training set" in the common AI context.
9. How the ground truth for the training set was established
As there is no mention of a "training set" in the context of an AI/ML algorithm in this document, this information is not provided. The "ground truth" for the original device's AKIRISK™ Score would have been established through extensive clinical studies comparing the biomarker levels and calculated scores to the actual development of AKI in patients, likely utilizing clinical diagnoses and outcomes as the reference. However, these details are not part of this specific Special 510(k) submission.
§ 862.1220 Acute kidney injury test system.
(a)
Identification. An acute kidney injury test system is a device that is intended to measure one or more analytes in human samples as an aid in the assessment of a patient's risk for developing acute kidney injury. Test results are intended to be used in conjunction with other clinical and diagnostic findings, consistent with professional standards of practice, including confirmation by alternative methods.(b)
Classification. Class II (special controls). The special controls for this device are:(1) Premarket notification submissions must detail an appropriate end user device training program that will be offered while marketing the device as part of your efforts to mitigate the risk of incorrect interpretation of test results.
(2) As part of the risk management activities performed as part of your 21 CFR 820.30 design controls, you must document the appropriate end user device training program provided in your premarket notification submission to satisfy special control 21 CFR 862.1220(b)(1) that will be offered while marketing the device as part of your efforts to mitigate the risk of incorrect interpretation of test results.
(3) Robust clinical data demonstrating the positive predictive value, negative predictive value, sensitivity and specificity of the test in the intended use population must be submitted as part of the premarket notification submission.