Search Results

The ABL835 FLEX analyzer is intended for: in vitro testing of pleural fluid samples for the pH parameter. The pH measurement of pleural fluid can be a clinically useful tool in the management of patients with parapneumonic effusions. Critical values: pH >7.3 is measured in uncomplicated parapneumonic effusions. All pleural effusions with a pH of <7.3 are referred as complicated parapneumonic effusions; they are exudative in nature.

Device Description

ABL835/ABL830/ABL825/ABL820/ABL815/ABL810/ABL805 FLEX analyzers are several models of the same analyzer for the measurement of blood gas, pH, electrolyte, metabolite, cooximetry, and expired air for the parameters p02 and pCO2. An additional indication, namely the measurement of pH in pleura fluids, has been introduced for the ABL835 FLEX analyzer. This additional indication is based on a further development of the software used in all ABL800 FLEX (and ABL700 before that).

AI/ML Overview

Here's an analysis of the provided text regarding the ABL835 FLEX analyzer and its acceptance criteria, structured to answer your questions:

The provided document describes the Radiometer ABL835 FLEX analyzer, specifically focusing on the new indication for measuring pH in pleural fluids. The acceptance criteria and performance studies are presented to demonstrate substantial equivalence to a predicate device.

1. Table of Acceptance Criteria and Reported Device Performance

The direct acceptance criteria values are not explicitly stated in a threshold format (e.g., "bias must be < X"). Instead, the document defines acceptance through comparison with a predicate device and established guidelines (NCCLS). The performance claims are related to precision and method comparison, demonstrating acceptable agreement with the predicate.

Performance Metric	Acceptance Criteria (Implied / Guideline)	Reported Device Performance (ABL835 FLEX)
Precision (Repeatability S₀)	Acceptable precision according to "NCCLS EP5-A2" guideline	pH 7.1: 0.013pH 7.3: 0.009pH 7.5: 0.005
Precision (Total Precision Sₓ)	Acceptable precision according to "NCCLS EP5-A2" guideline	pH 7.1: 0.029pH 7.3: 0.019pH 7.5: 0.027
Method Comparison (Slope)	Within 10% difference from predicate (implied acceptance)	1.063 (6.3% difference from ideal 1.0, which is ≤ 10%)
Method Comparison (Y-intercept)	Data coherence, 95% CI of regression includes identity line (implied acceptance)	-0.446; linear fit intersects identity line (X=Y) at pH 7.079. 95% Confidence Interval of linear regression covers the X=Y line from pH 7.0 to 7.5.
Method Comparison (Bias at critical point)	Considered acceptable, given sample nature and clinical context	At pH 7.3, ABL835 measures 0.0138 above Roche analyzer (considered acceptable).
Linearity (R-value)	Demonstrate linear fit of the method	R = 0.994

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

Precision Study:
- Sample Size:
  - pH 7.1: 244 observations
  - pH 7.3: 248 observations
  - pH 7.5: 248 observations
- Data Provenance: Not explicitly stated, but typically these samples would be prepared controls or simulated clinical samples in a laboratory setting for reproducibility. The document does not specify country of origin.
Method Comparison and Linearity Study:
- Sample Size: 58 samples (referred to as "patient samples" in the method comparison study and "58 samples" for linearity).
- Data Provenance: The method comparison study states it used "patient samples." The country of origin is not specified, nor is whether the data was retrospective or prospective.

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

The document does not mention the use of experts to establish ground truth for the quantitative pH measurements in the test set. Instead, the ground truth for method comparison is defined by comparison to a recognized predicate device (Roche Omni C) through direct measurement. For precision, the ground truth is against the expected value of the control material or sample being repeatedly measured.

4. Adjudication Method for the Test Set

No adjudication method is mentioned, as the studies involve direct quantitative measurements against a predicate device or for precision. This is not a study design where expert adjudication would typically be applied.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No MRMC comparative effectiveness study was conducted or mentioned in the provided text. The device is an automated analyzer, and the study focuses on its analytical performance rather than human interpretation with or without AI assistance.

6. Standalone Performance Study (Algorithm Only Without Human-in-the-Loop Performance)

Yes, the studies presented (Precision, Method Comparison, Linearity) are standalone performance studies. They evaluate the analytical performance of the ABL835 FLEX analyzer itself in measuring pH in pleural fluids, without human interpretation as part of the primary measurement.

7. Type of Ground Truth Used

Precision: The ground truth for precision is statistical (mean, standard deviation) derived from repeated measurements of samples with known characteristics.
Method Comparison/Linearity: The ground truth is defined by the measurements obtained from the predicate device, the Roche Omni C analyzer, for the same patient samples.

8. Sample Size for the Training Set

The document does not mention a "training set" in the context of device development. This suggests that the device does not employ machine learning or AI models that require explicit training data in the way, for example, an image recognition algorithm would. The device's operation is based on established electrochemical (potentiometric) principles.

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

As no training set is mentioned or implied for this type of device and submission, this question is not applicable. The device relies on physical and chemical principles, not data-driven machine learning models that require a "training set" with established ground truth.

Ask a Question

Ask a specific question about this device

Page 1 of 1