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The i-STAT Alinity System with i-STAT Sodium test is intended for use or clinical laboratory settings. The i-STAT Alinity System with Sodium test is intended for the quantitative measurement of sodium in arterial and venous whole blood.

Sodium measurements are used for monitoring electrolyte imbalances.

For in vitro diagnostic use.

The i-STAT Alinity System is a handheld, in vitro diagnostic analytical device designed to run i-STAT test cartridges. The system is designed for use at or near point of patient care, by trained medical professionals and is for prescription use only and is for use in point of care and laboratory settings.

The i-STAT Alinity System is comprised of the instrument, rechargeable battery, base station, electronic simulator, control material, printer and i-STAT test cartridges. The i-STAT Alinity Instrument features a barcode scanner, user interface with touch screen display and wireless capability. The instrument reports quantitative results within approximately 2 minutes.

The i-STAT cartridge contains test reagents which are located on the biosensors chips. The instrument interacts with the cartridge to move fluid across the biosensors and generate a quantitative result. Cartridges require two to three drops of whole blood which are typically applied to the cartridge using a syringe.

Here's an analysis of the provided text regarding the acceptance criteria and study for the i-STAT Alinity System with i-STAT Sodium test:

1. Table of Acceptance Criteria and Reported Device Performance

The document doesn't explicitly state formal "acceptance criteria" for each performance characteristic in a table format. However, the performance studies report findings that implicitly serve as evidence that the device meets certain quality standards. I will infer the implied acceptance criteria based on the reported results and common professional standards for in vitro diagnostic devices.

2. Sample Size Used for the Test Set and Data Provenance

• Precision (Aqueous Materials): 80 tests per level (N=80) for 5 levels.
• Precision (Whole Blood): 21 test results per sample for each of the 3 samples (total 63 tests per site, across 3 sites). The document refers to "venous whole blood (native or altered) samples."
• Linearity: Not explicitly stated, but "a series of sodium concentration levels in whole blood."
• Recovery: "a series of sodium concentration levels in whole blood."
• Limit of Quantitation (LoQ): Not explicitly stated, but "whole blood that was altered to low sodium concentrations (< 100 mmol/L)."
• Interference: "whole blood and plasma test samples"
• Anticoagulant Study: 40 blood samples.
• Method Comparison with Predicate Device: 174 subjects using whole blood (venous or arterial) samples.
• Data Provenance: The studies are described as being conducted at "one site" for aqueous precision, "3 point of care sites" for whole blood precision, and "4 point of care sites" for the method comparison. The nature of these sites (e.g., hospitals, clinics) and their geographical location (e.g., country of origin) are not specified. The data is prospective as it involves testing the device under specific experimental conditions.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts

There is no mention of human experts being used to establish a "ground truth" for the test set in the traditional sense of diagnostic imaging or clinical subjective assessment. For this type of in vitro diagnostic device (quantitative measurement of sodium), the "ground truth" is typically established by:

• Reference Methods: Highly accurate and precise laboratory methods (e.g., flame photometry, ion-selective electrodes on validated lab analyzers).
• Predicate Device: For method comparison studies, the performance of an already legally marketed device (the i-STAT 1 Wireless Analyzer in this case) serves as the comparator or "reference."

Therefore, the concept of "number of experts" and their "qualifications" for establishing ground truth as one might find in an AI imaging study is not applicable here.

4. Adjudication Method for the Test Set

Adjudication methods (like 2+1, 3+1) are typically used in studies where there is subjective interpretation by multiple human readers (e.g., radiologists reviewing images). Since this is an in vitro diagnostic device for quantitative chemical analysis, there is no subjective human interpretation that would require an adjudication method. The output is a numerical value.

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

No. An MRMC comparative effectiveness study is designed for scenarios involving human readers (e.g., clinicians, radiologists) interpreting cases, often with and without AI assistance, to assess the impact of AI on their performance. This device is an automated, standalone in vitro diagnostic system that provides quantitative measurements of sodium. It does not involve human "readers" interpreting output in a way that an MRMC study would be applicable, nor does it involve "AI assistance" for human interpretation.

6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done

Yes, the studies described are all standalone performance evaluations of the i-STAT Alinity System. The device itself (instrument and cartridge) performs the measurement and generates a numerical result. The studies assess the analytical performance of this system without requiring human interpretation as part of the primary measurement process. The only "human" involvement is in operating the device and collecting samples, but not in interpreting a diagnostic output in a subjective manner.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

For the quantitative measurement of sodium, the ground truth is established through:

• Reference Methods / Known Concentrations: For precision, linearity, recovery, LoQ, and interference studies, the "ground truth" often involves materials (aqueous or whole blood) with known or precisely measured sodium concentrations using a highly accurate reference method.
• Predicate Device Performance: For the method comparison study, the "ground truth" (or more accurately, the comparator) is the result obtained from the legally marketed predicate device (i-STAT 1 Wireless Analyzer). The goal is to show substantial equivalence, not necessarily absolute truth against a gold standard reference method for every sample, though the predicate itself would have been validated against such methods.

8. The Sample Size for the Training Set

The document describes performance evaluation studies for the finished device. It does not provide information on the sample size used for training or developing the algorithms within the i-STAT Alinity System. This kind of information is typically considered proprietary and not usually disclosed in a 510(k) summary, which focuses on validation of the final product.

9. How the Ground Truth for the Training Set was Established

Similar to point 8, the document does not provide information on how the ground truth for any potential training set was established, as it focuses on the validation of the final device's performance rather than its development. Any algorithms or internal calibration look-up tables in such a device would have been developed using internally generated data, with ground truth established through various analytical chemistry methods and potentially large datasets, but these details are not provided here.

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