(55 days)
The Stat Profile® Prime ABG Analyzer System is intended for in vitro diagnostic use by health care professionals in clinical laboratory settings and for point-of-care usage for the quantitative determination of pH, PCO2, and PO2 in heparinized whole blood.
PCO2, PO2, pH: Whole blood measurement of blood gases is used in the diagnosis and treatment of life threatening acid-base disturbances.
The Stat Profile® Prime ABG Analyzer is a small, low cost blood gas analyzer for laboratory and point-of-care use. The sensors and flow path have been integrated into one replaceable microsensor card, which is replaced periodically according to usage. The product, consumables, installation instructions and packaging are designed for easy customer installation.
Whole blood specimens are aspirated into the analyzer's microsensor card from syringes, tubes, or capillary blood collection devices using a peristaltic pump and a sampling probe. The disposable microsensor card contains the analytical flow path and the measurement sensors (pH, PCO2, and PO2). Once the analysis measurement is complete, the whole blood specimen is automatically flushed out of the microsensor card flow path and into a self-contained waste collection bag contained within the disposable calibrator cartridge.
The Stat Profile Prime ABG Analyzer has an enhanced test menu and multiple quality control options. Both traditional Internal and External liquid QC shall be offered, as well as an on-board Quality Management System (QMS), an electronic monitoring approach that insures the analyzer is working properly.
As with the predicate, the Stat Profile Prime ABG Analyzer is microprocessor-based and incorporates:
- traditional sensor technology to measure blood pO2 ●
- ion selective electrode technology to measure pH and pCO2
Here's a breakdown of the acceptance criteria and the study details for the Stat Profile® Prime ABG Analyzer System, based on the provided document:
1. Acceptance Criteria and Reported Device Performance
The document describes performance in terms of Method Comparison Studies (slope, intercept, correlation coefficient 'r') and Total Imprecision (SD and %CV). While explicit "acceptance criteria" are not listed as pass/fail thresholds in a dedicated table, the study aims to demonstrate substantial equivalence to a predicate device and safety/effectiveness for point-of-care use. The reported performance shown below reflects typical metrics for establishing analytical performance.
Method Comparison (POC vs. Trained Healthcare Professional)
| Parameter | Whole Blood Range | Slope | Intercept | r | Notes |
|---|---|---|---|---|---|
| pH | |||||
| Syringe Mode | 6.785 - 7.767 | 0.997 | 0.018 | 0.999 | Good correlation and agreement |
| Capillary Mode | 6.791 - 7.737 | 0.993 | 0.047 | 0.998 | Good correlation and agreement |
| PCO2 mmHg | |||||
| Syringe Mode | 4.3 - 193.0 | 1.001 | 1.063 | 0.998 | Good correlation and agreement |
| Capillary Mode | 3.2 - 192.2 | 0.984 | 1.347 | 0.997 | Good correlation and agreement |
| PO2 mmHg | |||||
| Syringe Mode | 11.8 - 755.3 | 1.015 | -0.939 | 1.000 | Excellent correlation and agreement |
| Capillary Mode | 13.1 - 672.9 | 1.041 | -2.761 | 0.999 | Excellent correlation and agreement |
Total Imprecision Performance (Combined External Controls)
| Parameter | Pooled Mean | N | Within Run SD (Sr) | Within Run %CV | Total Imprecision SD (St) | Total Imprecision %CV |
|---|---|---|---|---|---|---|
| Level 1 | ||||||
| pH | 7.152 | 120 | 0.004 | 0.056 | 0.005 | 0.070 |
| PCO2 | 61.3 | 120 | 0.8 | 1.3 | 1.7 | 2.7 |
| PO2 | 64.0 | 120 | 1.6 | 2.5 | 3.2 | 5.0 |
| Level 2 | ||||||
| pH | 7.367 | 120 | 0.002 | 0.027 | 0.003 | 0.041 |
| PCO2 | 41.4 | 120 | 0.4 | 1.0 | 0.6 | 1.5 |
| PO2 | 101.7 | 120 | 1.4 | 1.4 | 3.0 | 2.9 |
| Level 3 | ||||||
| pH | 7.560 | 120 | 0.006 | 0.079 | 0.007 | 0.093 |
| PCO2 | 25.5 | 120 | 0.8 | 3.1 | 1.2 | 4.7 |
| PO2 | 139.8 | 120 | 1.7 | 1.2 | 4.0 | 2.8 |
2. Sample Size Used for the Test Set and Data Provenance
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Sample Size (Method Comparison):
- Syringe Mode: 188 specimens
- Capillary Mode: 127 specimens
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Data Provenance: The method comparison data was collected from three point-of-care (POC) sites: a cardiovascular intensive care unit (CVICU), a medical intensive care unit (MICU), and a pulmonary care unit (PCU). The specimens used were described as "quality control materials or discarded blood gas specimens." This implies the data is prospective in nature, collected specifically for this study. The country of origin is not explicitly stated but implied to be the USA given the FDA submission.
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Sample Size (Imprecision): For total imprecision, "3 levels of Stat Profile Prime External Quality Control material (Levels 1-3)" were run in duplicate each day for 20 runs on 3 Stat Profile Prime ABG analyzers. This resulted in 120 data points (N=120) for each parameter at each level (3 levels x 2 duplicates x 20 runs = 120; or 3 analyzers x 20 runs x 2 duplicates = 120).
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
The study involved a comparison between "trained Healthcare Professionals" (THPs) and "POC personnel". The THPs likely represent the reference standard against which the POC measurements were compared.
- Number of Experts: The document does not specify a distinct number of "experts" for establishing ground truth in the traditional sense. Instead, it compares results from "trained Healthcare Professionals" to those from "POC personnel." It mentions that a total of 35 respiratory therapy and 17 Nursing POC personnel participated from the 3 POC settings. The THPs would be the analogous "experts" in this context.
- Qualifications of Experts: The POC personnel are described as "trained, qualified staff found in typical POC sites where blood gas analyzers are utilized." The "Trained Healthcare Professional" (THP) group implies similarly qualified individuals. Specific years of experience or credentials (e.g., "Radiologist with 10 years of experience") are not specified in the document.
4. Adjudication Method for the Test Set
The document does not describe an adjudication method for the test set. The comparison was reported as direct measurement agreement between two groups of users (POC vs. THP) on the same specimens or between the device and its own external quality controls. There is no mention of a third-party review or consensus process for discrepancies.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- Not Applicable. This document describes a submission for an in vitro diagnostic device (a blood gas analyzer), not a medical imaging device that typically uses MRMC studies to evaluate reader performance. The study assesses the device's analytical performance and its usability by different user groups (THP vs. POC personnel), not the diagnostic accuracy improvement of human readers using AI.
6. Standalone Performance Study (Algorithm only without human-in-the loop)
- Yes, in essence. The entire evaluation of the Stat Profile® Prime ABG Analyzer is focused on its standalone analytical performance. The comparisons are between the device operated by different user groups or against quality control materials. The device is the "algorithm" and instrument combined. The "method comparison studies" and "precision/reproducibility studies" are precisely standalone performance evaluations comparing the device's output to a recognized reference or against itself over time. The "POC vs Trained Healthcare Professional" comparison demonstrates that the device performs equivalently when used by different types of trained personnel, implying a robust standalone performance regardless of minor user variation.
7. Type of Ground Truth Used
- Reference Method / External Quality Controls:
- For the method comparison study (POC vs. THP), the device measurements obtained by "Trained Healthcare Professionals" served as the reference standard against which the "POC personnel" measurements were compared. This implies a comparison against a clinical reference measurement established by experienced users of the device or similar devices.
- For the imprecision study, Stat Profile Prime External Quality Control material (Levels 1-3) served as the ground truth, as the device's performance was assessed by measuring these known control materials.
8. Sample Size for the Training Set
- The document does not explicitly describe a "training set" in the context of machine learning. This is a medical device submission based on analytical performance and substantial equivalence, not typically an AI/ML device that requires distinct training and test sets for model development. The device uses "traditional sensor technology" and "ion selective electrode technology," implying established electrochemical principles rather than data-driven machine learning models requiring extensive training data.
9. How the Ground Truth for the Training Set Was Established
- As there's no explicit mention of a machine learning "training set," the concept of establishing ground truth for it is not applicable to this document. The device's performance is validated against established laboratory practices, reference methods, and quality control materials.
§ 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.