(279 days)
The Wescor ChloroChek Chloridometer test system is intended for the quantitative in vitro diagnostic determination of chloride in human sweat using the principle of coulometric titration. Sweat chloride measurements are used in the diagnosis of Cystic Fibrosis. It is for use in Clinical Laboratory settings. The Wescor ChloroChek Chloridometer test system consists of the ChloroChek Chloridometer and the ChloroChek Reagent Set.
The ChloroChek Reagent Set (SS-248) is to be used on the ChloroChek. It is used as the titration matrix during the titration process.
The 100 mmol/L NaCl/H2O Standard Solution (SS-251), is to be used on the ChloroChek. It is used as a calibration verifier, and quality control solution.
The Wescor Sweat Controls (SS-150), levels #1, #2, and #3, are to be used on the ChloroChek. They are used as quality control solutions.
The CHLOROCHEK™ Chloridometer® test system includes the ChloroChek Chloridometer analyzer and the ChloroChek Reagent Set. The system is for in-vitro diagnostics intended to measure the level of chloride in human sweat. It is a bench top chloride titrator for laboratory determinations of chloride concentrations.
The Wescor CHLOROCHEK™ Chloridometer® test system is intended for the quantitative in vitro diagnostic determination of chloride in human sweat. Sweat chloride measurements are used in the diagnosis of Cystic Fibrosis.
Here's an analysis of the acceptance criteria and study information provided:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Measuring Range | 10 mmol/L to 160 mmol/L |
| Precision | Total |
| Low concentration (24mmol/L): CV = 4.0% | |
| Medium concentration (49mmol/L): CV = 1.7% | |
| High concentration (100mmol/L): CV = 1.0% | |
| 100 mmol/L standard solution: CV = 1.0% | |
| 10 mmol/L standard solution: CV = 5.6% (SD 0.6 mmol/L) | |
| Method Comparison (vs. Predicate Device) | y = 0.9992x + 0.8754, r² = 0.9886 |
| Range tested (non-spiked and spiked): 8.0 to 642 U/L |
2. Sample Size Used for the Test Set and Data Provenance
The provided document describes a precision study and correlation studies for the device.
- Precision Study Test Set: The study tested three sweat levels (low, medium, high), a 100 mmol/L standard solution, and a 10 mmol/L standard solution. Specific numbers of individual samples for each level are not explicitly stated, but it involved multiple measurements over 10 days.
- Method Comparison Test Set: The range tested for the method comparison was 8.0 to 642 U/L (non-spiked and spiked). The specific number of samples (e.g., patient samples, spiked samples) used for this comparison is not explicitly stated.
- Data Provenance: The document does not specify the country of origin of the data or whether the study was retrospective or prospective. It implies the studies were conducted by the manufacturer, ELITechGroup Wescor.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
For an in vitro diagnostic device measuring a quantitative value, the "ground truth" is typically the reference method or the true concentration of the analyte, rather than expert consensus on interpretation.
- In the context of the precision study, the ground truth is based on the known concentrations of the standard solutions and the established values of the sweat control levels.
- For the method comparison study, the ground truth is the measurement obtained by the predicate device (Buchler Instruments, Chloridometer®).
- Therefore, the concept of "experts used to establish ground truth" with specific qualifications is not applicable in the same way it would be for image-based diagnostic systems.
4. Adjudication Method for the Test Set
As this is a quantitative measurement device for a chemical analyte, an adjudication method in the sense of resolving discrepancies between expert interpretations is not applicable. The performance is assessed against established quantitative metrics (precision, correlation with a predicate).
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 was not done. This device is a standalone in vitro diagnostic instrument, not an AI-assisted diagnostic tool that requires human interpretation. The concept of human readers improving with or without AI assistance is not applicable here.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Yes, a standalone performance study was done. The entire precision study and method comparison study describe the performance of the Wescor CHLOROCHEK™ Chloridometer® test system as a standalone device, measuring chloride levels without human interpretation as the primary outcome. The system produces a quantitative value (mmol/L) directly.
7. The Type of Ground Truth Used
- The ground truth for the precision study was established using standard solutions (10 mmol/L, 100 mmol/L NaCl/H2O) and sweat control solutions (levels #1, #2, and #3) with known chloride concentrations.
- The ground truth for the method comparison study was the results obtained from the predicate device (Buchler Instruments, Chloridometer®), which serves as the reference method for comparison.
8. The Sample Size for the Training Set
- The document does not provide information on a "training set" in the context of machine learning or AI. This device is an instrument for chemical analysis, not a learning algorithm. The studies conducted (precision, method comparison) are verification and validation studies of the instrument's performance.
9. How the Ground Truth for the Training Set was Established
- As there is no "training set" defined for this type of device, this question is not applicable.
§ 862.1170 Chloride test system.
(a)
Identification. A chloride test system is a device intended to measure the level of chloride in plasma, serum, sweat, and urine. Chloride measurements are used in the diagnosis and treatment of electrolyte and metabolic disorders such as cystic fibrosis and diabetic acidosis.(b)
Classification. Class II.