(241 days)
RAPIDPoint® 400/405/500 systems are intended for in vitro testing of pleural fluid samples for the pH parameter. Test systems are intended for use in point of care or laboratory settings.
The pH measurement of pleural fluid can be a clinically useful tool in the management of patients with parapneumonic effusions.
The following critical value applies to pleural fluid pH: pH > 7.3 is measured in uncomplicated parapneumonic effusions. All pleural fluids with a pH measurement
The RP400/405/500 system is a point-of-care and laboratory testing blood gas analyzer and currently measures a variety of parameters. With this planned release of software, the ability to measure pH in Pleural Fluid will be added to the system.
The pleural fluid pH measurement provides important information for the diagnosis of exudative pleural effusions. The RAPIDPoint® 400/405/500 system is intended for in vitro testing of pleural fluid samples for the pH parameter. This test system is intended for use in point of care or laboratory settings. Pleural fluid pH testing follows the same principles as whole blood pH testing. The notation of pH expresses the hydrogen ion activity in a solution as the negative logarithm of the hydrogen ion concentration. The pleural fluid pH measurement uses the potentiometric method using ion selective electrode (ISE) technology.
The provided text describes the analytical performance of the RAPIDPoint® 400/405/500 Systems for measuring pH in pleural fluid. The device is a blood gas analyzer that has been granted a 510(k) clearance (K122539) to include pleural fluid pH measurement.
Here's a breakdown of the requested information based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The submission does not explicitly state pre-defined acceptance criteria for the method comparison study in terms of specific ranges for slope, intercept, RMSE, or r². However, it states that "The results for the RP405 vs. the predicate device met the acceptance criteria" and "The results for the RP400 and RP500 vs. the predicate device met the acceptance criteria." This implies that internal acceptance criteria were used and successfully met.
For the precision studies, the acceptance criteria are not explicitly mentioned in terms of threshold values for WRSD, %WRCV, Total SD, or %Total CV. The tables simply report the measured precision values.
Therefore, the table below will present the reported performance, with the understanding that implied acceptance criteria were met.
| Study Type | Feature | Acceptance Criteria (Implied/Met) | Reported Device Performance (RP400/405/500) |
|---|---|---|---|
| Method Comparison | Slope | Implicitly met | RP400: 1.066, RP500: 1.059 |
| (vs. Predicate Device ABL 835 FLEX) | Intercept | Implicitly met | RP400: -0.437, RP500: -0.373 |
| RMSE | Implicitly met | RP400: 0.014, RP500: 0.016 | |
| Coefficient of Determination (r²) | Implicitly met | RP400: 0.99, RP500: 0.99 | |
| Linearity | Slope | Implicitly met | RP400: 1.066, RP405: 1.008, RP500: 1.059 |
| Intercept | Implicitly met | RP400: -0.437, RP405: -0.009, RP500: -0.373 | |
| r² | Implicitly met | RP400: 0.99, RP405: 0.95, RP500: 0.99 | |
| Precision with Controls | WRSD | Implicitly met | 0.002 - 0.004 |
| % WRCV | Implicitly met | 0.0 - 0.1 | |
| Total SD | Implicitly met | 0.002 - 0.004 | |
| % Total CV | Implicitly met | 0.0 - 0.1 | |
| Precision with Pleural Fluid | WRSD | Implicitly met | 0.006 - 0.012 |
| % WRCV | Implicitly met | 0.1 - 0.2 | |
| Total SD | Implicitly met | 0.008 - 0.019 | |
| % Total CV | Implicitly met | 0.1 - 0.3 | |
| Precision with Pleural Fluid (POC Study) | WRSD | Implicitly met | 0.011 - 0.019 |
| % WRCV | Implicitly met | 0.15 - 0.26 | |
| Total SD | Implicitly met | 0.02 - 0.03 | |
| % Total CV | Implicitly met | 0.21 - 0.42 |
2. Sample Size Used for the Test Set and Data Provenance
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Method Comparison and Linearity Test Set:
- RP405 vs. ABL835 FLEX: The sample size for the RP405 is not explicitly stated in the provided table for this comparison, only indicated by a missing number in a seemingly truncated table. However, other entries in the complete table indicate
nvalues (e.g.122for RP400 and RP500). - RP400 and RP500 vs. ABL835 FLEX: n = 122 pleural fluid samples per device (RP400 and RP500).
- Data Provenance: The specimens were "de-identified, leftover samples, collected both prospectively and retrospectively." The specific country of origin is not mentioned. Less than 20% of the samples were "altered samples."
- RP405 vs. ABL835 FLEX: The sample size for the RP405 is not explicitly stated in the provided table for this comparison, only indicated by a missing number in a seemingly truncated table. However, other entries in the complete table indicate
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Precision Test Set (Controls): n = 80 per control level per device (RP400, RP405, RP500).
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Precision Test Set (Pleural Fluid - Lab Study): n = 80 per fluid level per device (RP400, RP405, RP500).
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Precision Test Set (Pleural Fluid - Point of Care Study): n = 45 per fluid level per device (RP400, RP405, RP500).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This information is not provided in the document. The ground truth for the method comparison appears to be the measurements obtained from the predicate device (ABL835 FLEX Analyzer), which is itself a medical device measuring pH. For linearity and precision studies, it's based on the intrinsic performance of the devices against known buffered samples or the average of multiple measurements. There's no mention of human expert ground truth establishment for these analytical performance studies.
4. Adjudication Method for the Test Set
This is not applicable as the studies are analytical performance studies comparing device measurements or assessing device precision, not studies involving human interpretation or clinical adjudication.
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
This is not applicable. The device is an automated in vitro diagnostic instrument for measuring pH. It does not involve human readers interpreting images or data that would be augmented by AI.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
Yes, the entire study is a standalone performance evaluation of the RAPIDPoint® 400/405/500 Systems. The device operates automatically to measure pH in pleural fluid samples. The data presented demonstrates the analytical performance of the instrument, not its performance in conjunction with a human operator for interpretation.
7. The Type of Ground Truth Used
- Method Comparison: The "predicate device" (ABL835 FLEX Analyzer With Pleural pH, 510(k) K110416) served as the reference for ground truth in the method comparison studies.
- Precision Studies: For precision, the "mean" values for controls and pleural fluid samples served as the reference against which the variability was measured. These controls were buffered and CO2 tension was altered to three pH levels, implying controlled, known values.
- Linearity Study: Linearity was assessed using "linearity data for pleural fluid collected in the comparison study," which implies the predicate device's readings or a controlled series of samples with known pH values served as the reference.
8. The Sample Size for the Training Set
This information is not provided. As this is a 510(k) submission for a blood gas analyzer adding a new parameter, the underlying technology (ion selective electrode) is well-established. It's unlikely that a "training set" in the context of machine learning was used in the same way one would for an AI-powered device. The device's calibration and internal algorithms are based on established electrochemical principles, not a data-driven training process in the sense of AI.
9. How the Ground Truth for the Training Set was Established
This information is not provided and is likely not applicable in the context of this type of device. The calibration of the pH electrode in the device is performed using "2 point calibration using automated on-board reagent" with targeted calibration points of 6.8 and 7.4 pH. These are well-defined chemical standards that serve as the "ground truth" for the device's internal calibration.
§ 862.1120 Blood gases (P
CO2 , PO2 ) and blood pH test system.(a)
Identification. A blood gases (PCO2 , PO2 ) and blood pH test system is a device intended to measure certain gases in blood, serum, plasma or pH of blood, serum, and plasma. Measurements of blood gases (PCO2 , PO2 ) and blood pH are used in the diagnosis and treatment of life-threatening acid-base disturbances.(b)
Classification. Class II.