(269 days)
The i-STAT CHEM8+ cartridge with the i-STAT 1 System is in the in vitro quantification of total carbon dioxide in arterial or venous whole blood in point of care or clinical laboratory settings.
Carbon dioxide measurements are used in the diagnosis, monitoring, and treatment of numerous potentially serious disorders associated with changes in body acid-base balance.
The i-STAT CHEM8+ test cartridge contains test reagents to analyze whole blood at the point of care or in the clinical laboratory for total carbon dioxide (TCO2). The test is contained in a single-use, disposable cartridge. Cartridges require two to three drops of whole blood which are typically applied to the cartridge using a transfer device.
The i-STAT 1 Analyzer is a handheld, in vitro diagnostic analytical device designed to run only i-STAT test cartridges. The instrument interacts with the cartridge to move fluid across the sensors and generate a quantitative result (within approximately 2 minutes).
The i-STAT 1 System is comprised of the i-STAT 1 analyzer, the i-STAT test cartridges and accessories (i-STAT 1 Downloader/Recharger, electronic simulator and portable printer). The system is designed for use by trained medical professionals at the patient point of care or in the clinical laboratory and is for prescription use only.
The provided document is a 510(k) Summary for the Abbott Point of Care i-STAT CHEM8+ cartridge with the i-STAT 1 System, which performs in vitro quantification of total carbon dioxide (TCO2) in whole blood.
The acceptance criteria for the device are implicitly demonstrated through the performance characteristics presented, primarily focusing on precision, linearity, limit of quantitation (LoQ), and a method comparison study with a predicate device. The study aims to demonstrate substantial equivalence to the predicate device, SYNCHRON Systems TCO2 Reagent on UniCel DxC 600/800 SYNCHRON Clinical System (K042291).
Here's a breakdown of the requested information:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state "acceptance criteria" in a table format with specific numerical targets. Instead, performance is presented against standard clinical laboratory guideline (CLSI) expectations and compared to a predicate device. The "acceptance" can be inferred from the reported results meeting generally accepted analytical performance standards for clinical assays and demonstrating substantial equivalence to the predicate.
For this response, I will interpret "acceptance criteria" as the performance metrics evaluated and "reported device performance" as the results obtained from the study.
| Performance Metric | Implied Acceptance Criteria (based on CLSI guidelines and predicate comparison) | Reported Device Performance (i-STAT TCO2) |
|---|---|---|
| Precision (Aqueous Materials - Total Precision %CVT) | Generally low %CV for good precision | Level 1 (12.2 mmol/L): 2.4% |
| Level 2 (18.2 mmol/L): 1.7% | ||
| Level 3 (23.6 mmol/L): 2.7% | ||
| Level 4 (31.8 mmol/L): 4.3% | ||
| Level 5 (44.3 mmol/L): 2.1% | ||
| Precision (Whole Blood - Venous %CV) | Generally low %CV for good precision, especially at medical decision levels | 7-15 mmol/L: 5.1% |
| 15-25 mmol/L: 3.1% | ||
| 25-35 mmol/L: 2.3% | ||
| 35-47 mmol/L: 2.6% | ||
| Precision (Whole Blood - Arterial %CV) | Generally low %CV for good precision, especially at medical decision levels | 14-15 mmol/L: 4.0% |
| 15-25 mmol/L: 2.3% | ||
| 25-35 mmol/L: 1.9% | ||
| 35-50 mmol/L: 2.2% | ||
| Linearity (Regression for TCO2) | Slope close to 1, Intercept close to 0, R² close to 1 across the reportable range | Slope: 1.0281 |
| Intercept: -0.1259 | ||
| R²: 0.99379 | ||
| Range Tested: 4 - 52 mmol/L (Reportable Range: 5 - 50 mmol/L) | ||
| Limit of Quantitation (LoQ) | LoQ should be at or below the lower limit of the reportable range | LoQ: 4 mmol/L (below reportable range of 5 mmol/L) |
| Interference | No interference when the difference between spiked and control samples is ≤ 4 mmol/L or 10% of the mean TCO2 result (whichever is greater) | None of the tested substances (Bilirubin, Hemoglobin, Thiopental, Triglyceride, Intralipid) were found to interfere. |
| Method Comparison (Combined Venous & Arterial) | Passing-Bablok regression with slope close to 1, intercept close to 0, and high correlation (r close to 1) when compared to predicate device | N: 294 |
| Slope: 1.04 | ||
| Intercept: 0.17 | ||
| r: 0.97 | ||
| Method Comparison (Venous Whole Blood) | Passing-Bablok regression with slope close to 1, intercept close to 0, and high correlation (r close to 1) when compared to predicate device | N: 183 |
| Slope: 1.05 | ||
| Intercept: -0.01 | ||
| r: 0.98 | ||
| Method Comparison (Arterial Whole Blood) | Passing-Bablok regression with slope close to 1, intercept close to 0, and high correlation (r close to 1) when compared to predicate device | N: 111 |
| Slope: 1.03 | ||
| Intercept: 1.07 | ||
| r: 0.94 |
2. Sample Size Used for the Test Set and Data Provenance
- Precision (Whole Blood):
- Test Set Size: 279 samples (178 venous, 101 arterial).
- Data Provenance: Not explicitly stated as retrospective or prospective, but the phrasing "collected across three point of care sites" suggests these were fresh clinical samples collected for the purpose of the study (prospective or near-patient testing).
- Linearity (Whole Blood):
- Test Set Size: Not explicitly stated as a single number of samples, but involved preparing "whole blood samples of varying analyte levels that spanned the reportable range of the test."
- Data Provenance: Implied to be laboratory-prepared whole blood samples, likely prospective.
- Limit of Quantitation (LoQ):
- Test Set Size: Not explicitly stated as a single number of samples, but used "whole blood that was altered to low TCO2." The study was conducted over four (4) days using two (2) cartridge lots.
- Data Provenance: Implied to be laboratory-prepared whole blood samples, likely prospective.
- Interference:
- Test Set Size: Not explicitly stated as a single number of samples, but involved "whole blood test samples based on CLSI EP07-A2."
- Data Provenance: Implied to be laboratory-prepared whole blood samples, likely prospective.
- Method Comparison:
- Test Set Size: 294 specimens (183 lithium heparin venous whole blood, 111 lithium heparin arterial whole blood). 21 of these (7.14%) were "contrived" (meaning altered or spiked samples to extend the range).
- Data Provenance: Collected across three point of care sites, suggesting prospective clinical samples. The "contrived" samples are laboratory-prepared.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This type of information is generally not applicable for quantitative clinical chemistry assays like the one described. The "ground truth" for TCO2 is established by a reference method or a predicate device. In this case, the predicate device (SYNCHRON Systems TCO2 Reagent on UniCel DxC 600/800 SYNCHRON Clinical System) serves as the comparator or "reference method" for the method comparison study. Clinical experts are not typically involved in establishing the numerical ground truth for such analytes; rather, laboratory professionals operating validated equipment do.
4. Adjudication Method for the Test Set
Not applicable. Adjudication methods (like 2+1 or 3+1) are typically used in image-based diagnostic studies where human experts individually interpret results and a consensus process is needed to establish ground truth or resolve discrepancies. For this quantitative clinical chemistry device, the comparison is directly between numerical results from the candidate device and the predicate device/reference method.
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 device is a fully automated quantitative clinical chemistry analyzer. There are no "human readers" involved in interpreting results from the device in a diagnostic context that would require an MRMC study or AI assistance. The device provides a numerical output for TCO2.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
Yes, the studies presented are all standalone performance evaluations of the i-STAT CHEM8+ cartridge with the i-STAT 1 System. The device provides a direct quantitative measurement of TCO2 in whole blood without the need for human interpretation or further input once the sample is loaded and the test initiated. The precision, linearity, LoQ, interference, and method comparison studies evaluate the algorithm/device performance directly.
7. The Type of Ground Truth Used (Expert Consensus, Pathology, Outcomes Data, etc.)
The ground truth for the method comparison study was established by comparison to a legally marketed predicate device, the SYNCHRON Systems TCO2 Reagent on UniCel DxC 600/800 SYNCHRON Clinical System. For analytical performance studies (precision, linearity, LoQ, interference), the ground truth is based on the expected values of control materials or the known concentrations of prepared samples, often traceable to a reference measurement procedure (as mentioned for "Traceability: IFCC Reference Measurement Procedure" in Section 6, though this is for the candidate device, implying its own internal traceability).
8. The Sample Size for the Training Set
Not applicable. This device is a quantitative clinical chemistry analyzer, not a machine learning or AI-based diagnostic tool that typically requires a large "training set" in the conventional sense of AI development. While there is likely internal development and calibration data, the document does not refer to a distinct "training set" for an algorithm in the way it is discussed for AI/ML devices. The "training" for such devices often refers to rigorous calibration and verification procedures in the manufacturing process.
9. How the Ground Truth for the Training Set Was Established
Not applicable for the reasons stated in point 8.
§ 862.1160 Bicarbonate/carbon dioxide test system.
(a)
Identification. A bicarbonate/carbon dioxide test system is a device intended to measure bicarbonate/carbon dioxide in plasma, serum, and whole blood. Bicarbonate/carbon dioxide measurements are used in the diagnosis and treatment of numerous potentially serious disorders associated with changes in body acid-base balance.(b)
Classification. Class II.