(86 days)
The MICRO21 with ANA is a new MICRO21 intended use that follows the same process as the MICRO21 with WBC Diff, but instead locates, digitally stores and displays ANA Images to aid the technologist in performing an ANA Screen for Positive or Negative results. An ANA Screen is a microscopic exam of a patient serum sample that has been set-up using an indirect enzyme antibody test for the semi-quantitative detection of antinuclear antibody (ANA) which is an aid in the detection of systemic thematic disease.
The MICRO21™ with WBC Diff (White Blood Cell Differential) Ref. No. K925670/A is an automated microscopic system that locates WBCs, stores digital images of the cells and displays the images in an organized manner to aid technologists in performing the WBC Diff procedure. The MICRO21 process is substantially equivalent to the manual microscopic process.
The MICRO21 with ANA is a new MICRO21 intended use that follows the same process as the MICRO21 with WBC Diff, but instead locates, digitally stores and displays ANA Images to aid the technologist in performing an ANA Screen for Positive or Negative results.
Here's an analysis of the provided text, focusing on the acceptance criteria and study details for the MICRO21 with ANA device:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|
| Equivalence of ANA image presentation on MICRO21 to manual bright light microscopy | The study's conclusion explicitly states: "The image comparison performed in the Test Method confirms the safety and effectiveness of the MICRO21 with ANA for the intended use of location, storage and display of ANA images to aid the technologist in performing the ANA Test Screen." While specific metrics like sensitivity, specificity, or agreement rates are not provided in this summary, the core finding is that the MICRO21's image presentation is considered equivalent to the manual method for allowing technologists to perform the ANA screen. |
| Aid technologist in performing an ANA Screen for Positive or Negative results effectively. | The device does enable technologists to review images and make Positive/Negative determinations, and the study's conclusion supports its effectiveness in this role. The process involves the technologist confirming or changing the MICRO21's initial determination, implying it functions as an aid. No quantitative metrics for "aid effectiveness" are given. |
| Locate, digitally store, and display ANA Images accurately. | The system successfully locates well centers, captures four images per well, stores them, and displays them on a monitor for review. The test method used captured and stored images from 204 patient ANA tests, which were then displayed for review. The positive outcome of the study implies this function was performed adequately. |
| Substantial equivalence to the manual microscopic process for the specified ANA screening task. | The overall conclusion of the study, that the image comparison "confirms the safety and effectiveness for the intended use," supports the claim of substantial equivalence as it relates to the presentation of images for ANA screening. |
Important Note: The provided text is a summary of the 510(k) submission. It focuses on the equivalence of image presentation rather than providing detailed performance metrics (e.g., sensitivity, specificity, accuracy) that would typically be expected from a device making a diagnostic determination. The device's role is described as an "aid" to the technologist, implying human-in-the-loop performance is the ultimate measure.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: 204 patient ANA images.
- Data Provenance:
- Country of Origin: Not explicitly stated, but the mention of "Immuno Concepts®" suggests a US-based company, which (if it's the test site) implies US data. Could be from a clinical lab in any country where Immuno Concepts® operates.
- Retrospective or Prospective: Appears to be retrospective in nature, as the 204 patient ANA images were "identified by a technologist at Immuno Concepts® who manually read the 204 ANA patient tests using a bright light microscope" before being loaded onto the MICRO21. This suggests existing patient samples were used.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- Number of Experts: One technologist.
- Qualifications: "a technologist at Immuno Concepts® who manually read the 204 ANA patient tests using a bright light microscope." No further detail (e.g., years of experience, certification) is provided.
4. Adjudication Method for the Test Set
- Adjudication Method: Not applicable/explicitly stated as a multi-reader adjudication process. The ground truth was established by a single technologist's manual reading. The MICRO21 then displayed images, and a technologist (not necessarily the same one, but possibly) reviewed them and made a determination. The wording suggests a comparison to this single technologist's ground truth, rather than an adjudication of multiple expert opinions to establish ground truth for the study.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
- No, an MRMC comparative effectiveness study was not explicitly described. The study compares the image presentation of the device to the manual method, based on a single technologist's manual ground truth. While a technologist reviews the device's output, the design doesn't appear to be a formal MRMC study evaluating human reader performance with and without AI assistance with an effect size analysis. It's more of a usability/equivalence study for the displayed images.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
- No, a standalone performance study was not the primary focus or conclusion. The device is described as an "aid" to the technologist. While the MICRO21 makes an initial "Positive/Negative determination," the process explicitly states: "The technologist reviews the images and confirms that the MICRO21's Positive/Negative determination is correct. If not correct, the technologist changes the determination." Therefore, the final reported result is a human-in-the-loop performance, with the technologist retaining ultimate decision-making authority. The study confirms the image presentation for their review.
7. The Type of Ground Truth Used
- Expert Consensus: Specifically, the single expert opinion/manual reading of a technologist at Immuno Concepts® using a bright light microscope.
8. The Sample Size for the Training Set
- Not explicitly stated/provided. The document discusses the test method and samples used for testing, but does not give any details about a separate training set used for developing the MICRO21's initial determination capabilities. Given the era (1996) and the device's function (locating, storing, displaying images, with the technologist making the final call), it's possible the "determination" logic was rule-based or trained on a much smaller, internal dataset not detailed here.
9. How the Ground Truth for the Training Set was Established
- Not explicitly stated/provided. Without information on a specific training set, the method for establishing its ground truth cannot be determined from this document.
§ 864.5260 Automated cell-locating device.
(a)
Identification. An automated cell-locating device is a device used to locate blood cells on a peripheral blood smear, allowing the operator to identify and classify each cell according to type. (Peripheral blood is blood circulating in one of the body's extremities, such as the arm.)(b)
Classification. Class II (performance standards).