(406 days)
The i-STAT CHEM8+ cartridge with the i-STAT 1 System is intended for use in the in vitro quantification of sodium, potassium, chloride and blood urea nitrogen in arterial or venous 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 monitoring of diseases and clinical conditions that manifest high and low potassium levels.
Chloride measurements are primarily used in the diagnosis, monitoring, and treatment of electrolyte and metabolic disorders including, but not limited to, cystic fibrosis, diabetic acidosis, and hydration disorders.
Blood urea nitrogen measurements are used for the diagnosis, monitoring, and treatment of certain renal and metabolic diseases.
The i-STAT CHEM8+ test cartridge contains test reagents to analyze whole blood at the point of care or in the clinical laboratory for sodium, potassium, chloride and blood urea nitrogen. The test is contained in a single-use, disposable 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 i-STAT CHEM8+ cartridge with the i-STAT 1 System is intended for in vitro quantification of sodium, potassium, chloride, and blood urea nitrogen (BUN) in arterial or venous whole blood in point-of-care or clinical laboratory settings.
Here's an analysis of the acceptance criteria and the study results:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implied by the precision and method comparison studies aiming to demonstrate substantial equivalence to a predicate device (Beckman DxC). While explicit "acceptance criteria" are not listed in terms of specific thresholds for precision or correlation, the studies aim to show that the i-STAT CHEM8+ performs comparably to the predicate. The "Reportable Range" serves as one aspect of the acceptance criteria for each analyte.
| Analyte | Acceptance Criteria (Reportable Range) | Reported Device Performance (Precision) - Aqueous Materials (Total CV) | Reported Device Performance (Precision) - Whole Blood (Total %CV) (Range) | Reported Device Performance (Method Comparison - Correlation (r)) |
|---|---|---|---|---|
| Sodium | 100 - 180 mmol/L | 0.2% - 0.3% | 0.2% - 0.5% | 0.96 |
| Potassium | 2.0 - 9.0 mmol/L | 0.3% - 0.4% | 0.0% - 1.9% | 0.99 |
| Chloride | 65 - 140 mmol/L | 0.4% - 0.7% | 0.2% - 1.2% | 0.96 |
| BUN | 3 - 140 mg/dL | 0.8% - 3.7% | 0.0% - 9.4% | 0.99 |
Interference:
- Sodium: Increased results ≥ 3.1 mmol/L with Sodium Thiosulfate.
- Potassium: No identified interferents from the tested substances.
- Chloride: Increased results ≥ 2.4 mmol/L with Lithium Bromide, Increased results ≥ 4.19 mmol/L with Sodium Thiosulfate.
- BUN: Increased results ≥ 10.2 mmol/L with Triglyceride.
Limit of Quantitation (LoQ):
- Sodium: 91 mmol/L
- Potassium: 1.5 mmol/L
- Chloride: 56 mmol/L
- BUN: 1 mg/dL
2. Sample Sizes and Data Provenance
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Precision (Aqueous Materials):
- Sample Size: 80 or 81 data points for each of 5 levels per analyte (e.g., 81 for Sodium CV L1, 80 for Sodium CV L4). This study was conducted using multiple instruments and one test cartridge lot (implied prospective, in-house laboratory study).
- Data Provenance: Not explicitly stated as country of origin, but implies an in-house or specialized laboratory setting. It is a prospective analytical study.
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Precision (Whole Blood):
- Sample Size: 21 test results per sample per instrument (total of 21 test results per sample). This study involved at least 3 levels per analyte, 3 point of care sites, and 7 i-STAT 1 Analyzers. The number of unique whole blood samples is not specified, but the total number of measurements is significant (e.g., for Sodium, there are 19 rows of data, each representing a mean derived from 20 or 21 measurements).
- Data Provenance: Not explicitly stated as country of origin, but indicates multiple point-of-care sites. This is a prospective analytical study.
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Linearity:
- Sample Size: Not explicitly stated as a number of individual samples, but involves preparing "whole blood samples of varying analyte levels that spanned the reportable range of the tests."
- Data Provenance: Implied laboratory-based prospective analytical study.
-
Limit of Quantitation (LoQ):
- Sample Size: Not explicitly stated, but involved whole blood samples (and plasma for Chloride) altered to low concentrations and two test cartridge lots.
- Data Provenance: Implied laboratory-based prospective analytical study.
-
Interference:
- Sample Size: Not explicitly stated ("whole blood samples").
- Data Provenance: Implied laboratory-based prospective analytical study.
-
Method Comparison:
- Sample Size:
- Sodium: N=187
- Potassium: N=189
- Chloride: N=176
- BUN: N=184
- Data Provenance: Venous and arterial blood specimens were evaluated. Not explicitly stated as country of origin, but indicates clinical laboratory settings. This is a prospective analytical study comparing the i-STAT 1 System to the Beckman DxC.
- Sample Size:
3. Number of Experts and Qualifications for Ground Truth
This type of device (in vitro diagnostic for laboratory analytes) does not typically involve human expert adjudication for ground truth. The "ground truth" for analytical performance studies is established by:
- The reference method (Beckman DxC in the method comparison study).
- Precisely prepared calibrators or control materials with known concentrations (for precision, linearity, LoQ, and interference studies).
- NIST Standard Reference Materials (SRM) were used for traceability and calibration (NIST SRM 918, 919, 956, 912, 909).
4. Adjudication Method for the Test Set
Not applicable, as this is an analytical device for quantitative measurements, not an imaging device requiring expert clinical interpretation. The ground truth is established by reference measurement systems and documented analytical methods.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
No, an MRMC study was not done. This type of study is typically for evaluating the performance of diagnostic imaging devices that rely on human interpretation, often with and without AI assistance. This device is an in vitro diagnostic (IVD) analyzer that provides quantitative results.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) was done
Yes, the studies presented (precision, linearity, LoQ, interference, and method comparison) represent the standalone performance of the i-STAT CHEM8+ cartridge with the i-STAT 1 System. The device provides a direct quantitative measurement without human interpretation of its internal algorithm's output in the manner implied by "human-in-the-loop performance" for AI/ML devices.
7. The Type of Ground Truth Used
The ground truth for the analytical performance studies was established using:
- Reference instrumentation run by trained laboratory personnel: For the method comparison, the Beckman DxC clinical analyzer served as the comparative method.
- Prepared aqueous and whole blood materials with known analyte concentrations: Used for precision, linearity, LoQ, and interference studies.
- NIST Standard Reference Materials (SRM): Used for traceability and calibration.
8. The Sample Size for the Training Set
Not applicable. This device is a traditional in vitro diagnostic device, not an AI/ML device that requires a "training set" in the machine learning sense. The "training" for such devices typically refers to the development and optimization of the electrochemical sensors and algorithms during the R&D phase, which is not described in terms of a quantifiable "training set size" in a regulatory submission for a traditional IVD.
9. How the Ground Truth for the Training Set was Established
Not applicable, as there is no "training set" in the AI/ML context for this traditional IVD device. The accuracy of the device's measurement principles is established through rigorous analytical verification and validation using reference materials and comparative methods, as detailed in the performance characteristics section.
§ 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.