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The SelectaLyte™ Electrolyte Analyzer (Na+, K+, Cl-) is an in vitro device intended to be used for the measurement of ionized Sodium (Na+), Potassium (K+), and Chloride (Cl-) in serum and lithium heparin venous whole blood samples. The measurements are to be conducted by a trained professional in a clinical laboratory. For in vitro diagnostic use only.

The SelectaLyte Sodium (Na+) assay is intended to measure sodium. Measurements obtained by this device are used to monitor electrolyte balance in the diagnosis and treatment of aldosteronism, diabetes insipidus, adrenal hypertension, Addison's disease, dehydration, inappropriate antidiuretic hormone secretion, or other diseases involving electrolyte imbalance.

The SelectaLyte Potassium (K+) assay is intended to measure potassium. Measurements obtained by this device are used to monitor electrolyte balance in the diagnosis and treatment of disease conditions characterized by low or high blood potassium levels.

The SelectaLyte Chloride (Cl-) assays is intended to measure chloride. Measurements are used in the diagnosis and treatment of electrolyte and metabolic disorders such as cystic fibrosis and diabetic acidosis.

The SelectaLyte™ Electrolyte Analyzer (Na*, K*, Cl) is an automated, microprocessor-controlled electrolyte analyzer for measurement of Sodium (Na*), and Chloride (Cl`) in serum, whole blood and QC aqueous solutions. The SelectaLyte™ Electrolyte Analyzer (Na*, K*, Cl') utilizes ion selective electrodes (ISE) to measure test samples, and display the results automatically. The instrument features automatic and on-demand calibration, patient data storage, and interactive LCD touch screen.

Acceptance Criteria and Device Performance for SelectaLyte Electrolyte Analyzer (Na+, K+, Cl-)

The provided text details the performance evaluation of the SelectaLyte Electrolyte Analyzer as part of its 510(k) premarket notification. The acceptance criteria and the device's performance are primarily demonstrated through studies on precision, linearity, method correlation, and interference.

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria values in table format (e.g., "CV must be < X%"). However, the acceptance for each study is implicitly demonstrated by the successful completion of the CLSI (Clinical and Laboratory Standards Institute) guidelines and the reported results falling within acceptable laboratory practice (e.g., correlation coefficients close to 1, small biases relative to the predicate device, acceptable precision metrics). The "Reportable Range" serves as a key acceptance criterion for linearity and method correlation.

Here's a summary of the reported device performance, which implies that these values met the internal acceptance criteria for substantial equivalence:

Table 1: Reported Device Performance

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

• Precision Study:
  • Serum: N=80 for each of three levels of pooled human serum, for each analyte (Sodium, Potassium, Chloride). (2 machines, multiple users, 2 runs/day over 20 days = 80 measurements).
  • Whole Blood: N=40 for each of three levels of pooled human whole blood, for each analyte (Sodium, Potassium, Chloride). (40 replicates per sample after calibrations every 10 consecutive replicates).
• Linearity Study:
  • Serum: 4 replicates at each level, over 10 or 11 levels of concentration for each analyte. (e.g., Sodium: 10 levels * 4 replicates = 40 samples).
  • Whole Blood: 4 replicates at each level, over 10 or 11 levels of concentration for each analyte. (e.g., Sodium: 11 levels * 4 replicates = 44 samples).
• Method Correlation Study:
  • N=100 samples (serum and whole blood, respectively) for each analyte compared to the predicate device (AVL 9180 Electrolyte Analyzer). 10% of samples were spiked or diluted to span the claimed measuring ranges.
• Interference Study:
  • The number of samples for the interference study is not explicitly stated as a single "N". Multiple interferent substances were tested at various concentrations. The methodology follows CLSI EP07-A2. The highest concentration that did not show significant interference is reported.

Data Provenance: The document does not explicitly state the country of origin of the human serum or whole blood samples. It mentions "Pooled Human Serum" or "Human Whole Blood." The studies are retrospective as they were conducted as part of the 510(k) submission.

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

This device is an in vitro diagnostic (IVD) electrolyte analyzer. The "ground truth" for the test set is established by the analytical reference methods or predicate device measurements, not by human expert interpretation (e.g., radiologists reading images). Therefore, there were no "experts" in the sense of medical professionals adjudicating diagnostic test results for the test set.

4. Adjudication Method for the Test Set

Not applicable for this type of in vitro diagnostic device test. The "truth" is determined by the analytical performance of the device against reference methods or the legally marketed predicate device, as per CLSI guidelines, rather than human consensus or adjudication of clinical interpretations.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done

No, an MRMC comparative effectiveness study was not done. This type of study is primarily relevant for diagnostic imaging devices where human readers interpret medical images, and the AI's impact on their performance is being evaluated. For an IVD device like the SelectaLyte Electrolyte Analyzer, performance is assessed through analytical studies (precision, linearity, correlation) comparing the device's measurements to established standards or a predicate device.

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

Yes, the studies presented (Precision, Linearity, Method Correlation, Interference) are all "standalone" in nature for an IVD device. They evaluate the analytical performance of the SelectaLyte Electrolyte Analyzer itself, independent of immediate human interpretation of results, beyond the standard operation by a trained professional in a clinical laboratory. The device outputs numerical values for Na+, K+, and Cl-, and these values are compared to known concentrations or predicate device results.

7. The Type of Ground Truth Used

The ground truth used for performance evaluation varied by study:

• Precision: The ground truth is the inherent concentration of the analyte within the stable, homogeneous pooled human serum or whole blood samples, and the consistency of repeated measurements.
• Linearity: The ground truth is established by accurately prepared intermediate concentration samples through proportional mixing of high and low concentration pools, aiming for known, linearly distributed concentrations.
• Method Correlation: The ground truth is the measurements obtained from the legally marketed predicate device (AVL 9180 Electrolyte Analyzer). This demonstrates substantial equivalence.
• Interference: The ground truth is the expected analyte concentration in the presence of various potentially interfering substances, assessed against a baseline without the interferent, looking for significant bias.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" or "validation set" in the context of machine learning. This is a traditional IVD device, not an AI/ML-driven device. The studies described are validation studies performed on the final device to demonstrate its performance characteristics.

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

Not applicable. As noted above, this document describes the validation of a traditional IVD device, not the development or training of an AI/ML model. Therefore, there is no "training set" in the machine learning sense, nor is there ground truth established for such a set.

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