(29 days)
The Accu-Chek Active system is designed to quantitatively measure the concentration of glucose in capillary whole blood. The device is indicated for professional use and over-the-counter sale. The Accu-Chek Active system is indicated for use with capillary whole blood samples drawn from the fingertips, forearm, upper arm, thigh, calf and palm.
Instrument Operating Principle -- photometry
Reagent Test Principle -- glucose dehydrogenase
Here's an analysis of the provided text regarding the Accu-Chek Active System's acceptance criteria and study:
1. Table of Acceptance Criteria and Reported Device Performance
The provided summary focuses on demonstrating that the modified Accu-Chek Active System maintains its accuracy when used with alternate sampling sites (palm) compared to fingertip measurements, and that its performance for existing alternate sites (calf, thigh, upper arm) remains consistent.
Acceptance Criteria for Correlation (Implicit): The study aimed to demonstrate a "substantial correlation (r > 0.90)" between AST (Alternate Site Testing) results and finger results.
Reported Device Performance:
| AST Location | N | Range (mg/dL) | Slope | Slope 95% CI | Intercept | Intercept 95% CI | Correlation (r) | Std Error |
|---|---|---|---|---|---|---|---|---|
| Palm (near thumb) | 65 | 31-371 | 1.031 | (0.994, 1.067) | -0.5 | (-6.7, 5.6) | 0.990 | 11.0 |
| Palm (near small finger) | 65 | 31-371 | 1.019 | (0.978, 1.059) | 1.7 | (-5.1, 8.5) | 0.988 | 12.1 |
Conclusion regarding acceptance criteria: Both palm sampling sites achieved a correlation coefficient (r) of greater than 0.90 (0.990 and 0.988 respectively), indicating that the device met the implicit acceptance criterion for substantial correlation.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: 65 subjects for each palm alternate site (palm near thumb and palm near small finger), for a total of 130 samples specifically reported in the table. The phrase "With these data it is proved that the system accuracy with AST blood from calf, thigh and upper arm is unchanged from forearm" suggests additional data might have been collected for these sites, but the detailed statistics are only provided for the palm.
- Data Provenance: The study was "conducted at our manufacturing facility." This suggests it was an internal company study. There is no explicit mention of the country of origin for the data or whether it was retrospective or prospective. Given it's a study demonstrating consistent performance for a modified device, it is most likely a prospective study where samples were actively collected for the purpose of the study.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
This information is not provided in the document. For a blood glucose meter, the "ground truth" or reference method is typically an established laboratory reference analyzer, not expert consensus. The document does not specify the reference method used.
4. Adjudication Method for the Test Set
This is not applicable as the ground truth for a blood glucose meter is typically established by a laboratory reference method, not by human expert adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, and the effect size of how much human readers improve with AI vs without AI assistance
- Not applicable. This document describes a modification to a blood glucose meter, which is an in vitro diagnostic device. It does not involve human readers interpreting images or data, nor does it concern AI assistance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Yes, implicitly. The data presented are direct comparisons between the Accu-Chek Active System's readings from different sample sites. The performance metrics (slope, intercept, correlation) describe the device's accuracy without human intervention playing a role in interpreting the result displayed by the meter.
7. The Type of Ground Truth Used
The document does not explicitly state the specific reference method used to establish the "ground truth" or comparator for the finger results. However, for blood glucose meters, the standard ground truth is typically:
- A laboratory reference method (e.g., YSI analyzer, hexokinase method) run on a plasma sample, which is then mathematically converted to whole blood equivalent glucose values.
- Alternatively, the "finger results" from the Accu-Chek Active Meter itself could be considered the reference if the goal was solely to prove equivalence of AST to fingertip measurements with the same meter. The text "AST Sample versus Finger (Same Accu-Chek Active Meter)" suggests that the fingertip measurement from the same device served as the comparator for the AST readings.
8. The Sample Size for the Training Set
This information is not provided. The data presented is for the validation/test set. Blood glucose meters typically do not involve "training sets" in the same way machine learning algorithms do. Development and calibration would involve internal studies, but those are distinct from the validation study described here.
9. How the Ground Truth for the Training Set Was Established
- Not applicable / Information not provided. As mentioned above, a traditional "training set" with ground truth in the context of machine learning is not directly relevant here. For the internal development and calibration of the glucose meter, ground truth would have been established using highly accurate laboratory reference methods.
§ 862.1345 Glucose test system.
(a)
Identification. A glucose test system is a device intended to measure glucose quantitatively in blood and other body fluids. Glucose measurements are used in the diagnosis and treatment of carbohydrate metabolism disorders including diabetes mellitus, neonatal hypoglycemia, and idiopathic hypoglycemia, and of pancreatic islet cell carcinoma.(b)
Classification. Class II (special controls). The device, when it is solely intended for use as a drink to test glucose tolerance, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 862.9.