(268 days)
The i-STAT CG8+ cartridge with the i-STAT 1 System is in the in vitro quantification of sodium and potassium in arterial or venous whole blood in point of care or clinical laboratory settings.
The i-STAT CG8+ cartridge with the i-STAT 1 System is intended for use in the in vitro quantification of sodium in capillary whole blood in point of care or clinical laboratory settings.
Sodium measurements are used for monitoring electrolyte imbalances.
Potassium measurements are used in the diagnosis and cinical conditions that manifest high and low potassium levels.
The i-STAT CG8+ cartridge is used with the i-STAT 1 analyzer as part of the i-STAT 1 System and contains test reagents to measure sodium (Na) in arterial, venous or capillary whole blood and to measure potassium (K) in arterial and venous whole blood.
The i-STAT 1 System is an in vitro diagnostic (IVD) medical device intended for the quantitative determination of various clinical chemistry tests contained within i-STAT cartridges using whole blood. The i-STAT 1 System consists of a portable blood analyzer (i-STAT 1 analyzer), single-use disposable test cartridges (i-STAT cartridges), liquid quality control and calibration verification materials, and accessories (i-STAT 1 Downloader/Recharger, i-STAT Electronic Simulator and i-STAT 1 Printer). The i-STAT 1 System, including the i-STAT CG8+ cartridge, is designed for use by trained medical professionals in point of care or clinical laboratory settings and is for prescription use only.
The i-STAT CG8+ cartridge contains the required sensors, a fluid pack (calibrant pouch), a sample entry well and closure, fluid channels, waste chamber, and the necessary mechanical features for controlled fluid movement within cartridge. The i-STAT cartridge format allows all the tests in the cartridge to be performed simultaneously. All the test steps and fluid movement occur within the i-STAT CG8+cartridge. Cartridges require two to three drops of whole blood applied to the cartridge using a transfer device by the trained user before the cartridge is placed within the analyzer.
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 i-STAT CG8+ cartridge to move fluid across the sensors and generate a quantitative result (within approximately 2 minutes).
This document describes the performance of the i-STAT CG8+ cartridge with the i-STAT 1 System for the in vitro quantification of sodium (Na) and potassium (K) in whole blood. This is a medical device, and the provided text is a 510(k) summary, which is typically submitted to the FDA to demonstrate substantial equivalence to a legally marketed predicate device.
It's important to note that the provided text focuses on the analytical performance of a diagnostic device (measuring concentrations of substances), not an AI-assisted diagnostic device for interpreting images or other complex data. Therefore, many of the requested points regarding AI/MRMC studies, number of experts, adjudication methods, and ground truth establishment for complex AI algorithms are not applicable to this type of device and will not be found in the document.
Here's a breakdown of the requested information based on the provided text, focusing on the analytical performance validation:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state "acceptance criteria" in a single table. Instead, it presents performance characteristic studies (precision, linearity, detection limit, interference, method comparison, and matrix equivalence) with their respective results. The success of these studies implicitly serves as the acceptance criteria for the device to be considered substantially equivalent.
Below is a summary of the reported device performance for key analytical characteristics:
| Performance Metric | Test (Units) | Relevant Range / Levels | Acceptance Criteria (Implied by Study Design & Results) | Reported Device Performance (Summary) |
|---|---|---|---|---|
| Precision | Demonstrated low variability across multiple conditions | |||
| 20-Day Precision | Na (mmol/L) | 5 levels (approx. 99-181 mmol/L) | Low SD and %CV | SD: 0.17-0.32, %CV: 0.16-0.20 (Repeatability); Overall within-lab %CV ≤ 0.20 |
| K (mmol/L) | 5 levels (approx. 2.09-7.99 mmol/L) | Low SD and %CV | SD: 0.007-0.027, %CV: 0.25-0.37 (Repeatability); Overall within-lab %CV ≤ 0.41 | |
| Multi-Site/Operator (Aqueous) | Na (mmol/L) | 5 levels (approx. 100-181 mmol/L) | Low overall %CV | Overall %CV: 0.23-0.32 |
| K (mmol/L) | 5 levels (approx. 2.10-7.89 mmol/L) | Low overall %CV | Overall %CV: 0.39-1.05 | |
| Whole Blood Precision | Na (mmol/L) | Venous (100-180), Arterial (100-180), Capillary (100-180) | Low SD and %CV | Venous: SD 0.30-0.45, %CV 0.24-0.33; Arterial: SD 0.37-0.42, %CV 0.26-0.31; Capillary: SD 0.41-0.62, %CV 0.34-0.44 |
| K (mmol/L) | Venous (2.0-9.0), Arterial (2.0-9.0) | Low SD and %CV | Venous: SD 0.032-0.038, %CV 0.50-1.12; Arterial: SD 0.021-0.041, %CV 0.65-0.79 | |
| Linearity | Slope near 1, Intercept near 0, High R^2 | |||
| Na (mmol/L) | Reportable Range: 100-180 Tested Range: 91.3-209.8 | Meets reportable range | Slope: 1.005, Intercept: -0.525, R^2: 0.9996 | |
| K (mmol/L) | Reportable Range: 2.0-9.0 Tested Range: 1.79-10.04 | Meets reportable range | Slope: 1.011, Intercept: 0.002, R^2: 0.9994 | |
| Detection Limit (LoQ) | At or below lower limit of reportable range | |||
| LoQ | Na (mmol/L) | Reportable Range: 100 | ≤ 100 | Determined LoQ: 92 |
| K (mmol/L) | Reportable Range: 2.0 | ≤ 2.0 | Determined LoQ: 1.6 | |
| Analytical Specificity (Interference) | Na & K (mmol/L) | Various substances at toxic/pathological concentrations | Difference between control and test samples within allowable error (±Ea) | Most substances showed no interference. Noted interferences: |
- Cholesterol: Decreased Na results > 400 mg/dL
- Nithiodote (Sodium Thiosulfate): Increased Na results ≥ 2.1 mmol/L |
| Method Comparison | | | Slope near 1, Intercept near 0, High r | Substantially equivalent to predicate device |
| K (mmol/L) vs. Predicate (i-STAT CHEM8+) | Arterial/Venous | n=340 | Strong correlation & agreement | Slope: 1.00, Intercept: 0.00, r: 1.00. Bias at Medical Decision Levels (3.0, 5.8, 7.5): 0.00 |
| Na (mmol/L) vs. Predicate (i-STAT CHEM8+ or epoc Blood Analysis System) | Pooled: Arterial/Venous/Capillary | n=551 (pooled), n=209 (capillary only) | Strong correlation & agreement | Pooled: Slope: 1.00, Intercept: 0.00, r: 0.99. Bias at Medical Decision Levels (115, 135, 150): 0.0. Capillary only: Slope 1.00, Intercept 0.00, r 0.98. Bias 0.0. |
| Matrix Equivalence | | | Slope near 1, Intercept near 0, High r | Equivalence demonstrated |
| Na (mmol/L) | Venous/Arterial non-anticoagulated vs. with anticoagulant | n=295 | Strong correlation & agreement | r: 0.99, Slope: 1.00, Intercept: 0.00 |
| K (mmol/L) | Venous/Arterial non-anticoagulated vs. with anticoagulant | n=292 | Strong correlation & agreement | r: 0.99, Slope: 1.00, Intercept: 0.00 |
2. Sample Size Used for the Test Set and the Data Provenance
The "test set" in this context refers to the samples used in the analytical performance studies. The data provenance is described within each study:
- Precision/Reproducibility (Aqueous materials):
- 20-day precision: N=80 per level (5 levels) for Na and K. Conducted at "one site."
- Multi-site/operator precision: N=90-97 per level (5 levels) for Na and K. Conducted at "three (3) sites."
- Precision (Whole Blood):
- N varies by analyte and sample type/range (e.g., Na venous: 17, 99, 67; Na arterial: 2, 89, 62; Na capillary: 3, 56, 95; K venous: 27, 135, 19; K arterial: 23, 124, 6).
- Whole blood specimens collected "across multiple point of care sites." Capillary specimens involved "two individual fingersticks, collected independently by two operators."
- Linearity:
- Whole blood samples of "varying analyte levels" were used. Specific N not provided for this study.
- Detection Limit (LoQ):
- Whole blood that was altered to a low analyte level. Specific N not provided.
- Analytical Specificity (Interference):
- Whole blood samples were used. Specific N not provided, but interference determined by comparing "control sample" to "test sample."
- Method Comparison:
- K (Arterial/Venous): N=340. "Lithium heparin venous and arterial whole blood specimens collected across multiple point of care sites."
- Na (Pooled: Arterial/Venous/Capillary): N=551. "Venous and arterial" data pooled with "capillary whole blood specimens."
- Na (Capillary only): N=209. "Native and Contrived Capillary Specimens." Bias at Medical Decision Levels for "Native Capillary Specimens" (N=194).
- Matrix Equivalence:
- N=295 for Na, N=292 for K. "non-anticoagulated venous and arterial whole blood specimens."
Data Provenance: The data was collected from "multiple point of care sites" in the precision and method comparison studies. The document does not specify the country of origin or whether the studies were retrospective or prospective, though typical 510(k) studies for new devices are prospective analytical performance studies.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts
This type of device (in vitro diagnostic for chemical analysis) does not typically involve expert readers or adjudication for "ground truth" in the same way an AI imaging algorithm would. The "ground truth" for analytical performance is the reference measurement provided by a comparator method (e.g., the i-STAT CHEM8+ predicate device or "comparative method" lab instrument) or gravimetric/volumetric preparation for linearity and precision studies.
Therefore, there is no mention of "experts" (e.g., radiologists) establishing ground truth, nor their qualifications or numbers.
4. Adjudication Method for the Test Set
Not applicable. As noted above, this device does not involve human interpretation requiring adjudication. Performance is assessed by comparing quantitative results from the device against a known reference or comparative 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 is not an AI-assisted diagnostic device, nor does it involve human readers interpreting data. It's a quantitative measurement device.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
This is an algorithm/device-only performance study, as it's a fully automated in vitro diagnostic device. The performance data presented (precision, linearity, method comparison, etc.) reflects the standalone performance of the i-STAT CG8+ cartridge with the i-STAT 1 System. There is no human interpretation component in the measurement or output of the device.
7. The Type of Ground Truth Used
The "ground truth" in these analytical performance studies is established by:
- Reference materials/calibrators: For precision, linearity, and detection limit studies, defined aqueous or whole blood materials with known (or precisely determined) analyte concentrations are used.
- Comparator methods: For method comparison studies, the device's results are compared against a legally marketed predicate device (i-STAT CHEM8+ cartridge on the i-STAT 1 System) or another established "comparative method" (e.g., epoc Blood Analysis System) which serves as the reference, assumed to be accurate.
- Prepared samples: For linearity, samples are prepared with varying analyte levels.
8. The Sample Size for the Training Set
This document does not specify a "training set" size. For traditional in vitro diagnostic devices, there isn't a "training" phase in the machine learning sense. The device's algorithms (for sensor interpretation and calculation) are developed and validated in a more traditional engineering sense, not through iterative machine learning on a large dataset. The studies described are for validation or testing the final product's performance.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as there's no "training set" in the context of machine learning for this type of device. The ground truth for development and internal validation of such a device would likely be established through highly controlled laboratory measurements using reference methods and materials.
§ 862.1665 Sodium test system.
(a)
Identification. A sodium test system is a device intended to measure sodium in serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and treatment of aldosteronism (excessive secretion of the hormone aldosterone), diabetes insipidus (chronic excretion of large amounts of dilute urine, accompanied by extreme thirst), adrenal hypertension, Addison's disease (caused by destruction of the adrenal glands), dehydration, inappropriate antidiuretic hormone secretion, or other diseases involving electrolyte imbalance.(b)
Classification. Class II.