← Product Code [QKQ](/submissions/PA/subpart-d%E2%80%94pathology-instrumentation-and-accessories/QKQ) · K252762

# HALO AP Dx (K252762)

_Indica Labs, LLC · QKQ · Nov 25, 2025 · Pathology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/PA/subpart-d%E2%80%94pathology-instrumentation-and-accessories/QKQ/K252762

## Device Facts

- **Applicant:** Indica Labs, LLC
- **Product Code:** [QKQ](/submissions/PA/subpart-d%E2%80%94pathology-instrumentation-and-accessories/QKQ.md)
- **Decision Date:** Nov 25, 2025
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 864.3700
- **Device Class:** Class 2
- **Review Panel:** Pathology
- **Attributes:** Software as a Medical Device

## Indications for Use

HALO AP Dx is a software only device intended as an aid to the pathologist to review, interpret and manage digital images of scanned surgical pathology slides prepared from formalin-fixed paraffin embedded (FFPE) tissue for the purposes of pathology primary diagnosis. HALO AP Dx is not intended for use with frozen section, cytology, or non-FFPE hematopathology specimens. It is the responsibility of a qualified pathologist to employ appropriate procedures and safeguards to assure the quality of the images obtained and, where necessary, use conventional light microscopy review when making a diagnostic decision. HALO AP Dx is intended for use with the interoperable components specified in the Table below.

## Device Story

HALO AP Dx is a browser-based software-only device for viewing, manipulating, and managing digital pathology whole slide images (WSI). It ingests images from Hamamatsu NanoZoomer S360MD or Leica Aperio GT 450 DX scanners. Pathologists use the device in clinical settings to zoom, pan, annotate, and measure distances/areas on digital slides. The device fetches images from external storage for display on validated monitors. It aids pathologists in making primary diagnoses, which are documented in external Laboratory Information Systems. The device ensures pixel-level display equivalence to predicate image review software, supporting clinical decision-making by providing a digital alternative to conventional light microscopy.

## Clinical Evidence

No clinical data. Bench testing only. Pixel-wise comparison testing was performed on 30 H&E-stained FFPE slides across 6 configurations, comparing the subject device to predicate IRMS software. Results showed 95th percentile CIEDE2000 color differences were < 3 ΔE00, confirming identical image reproduction. Measurement accuracy for length (< 0.005 mm) and area (< 0.001 mm²) was verified using calibration slides. Turnaround time testing confirmed response times for opening, panning, and zooming met acceptance criteria.

## Technological Characteristics

Browser-based software-only device. Operates on Windows 11 (client) and Windows Server 2022/Ubuntu 22.04 (server). Supports SVS, DICOM, and NDPI file formats. Connectivity via 1 Gbps LAN. Validated for use with Microsoft Windows Defender, Trend Micro, and Webroot antivirus. No hardware components; relies on interoperable scanners and displays (Dell U3223QE, Barco MDPC-8127).

## Regulatory Identification

The whole slide imaging system is an automated digital slide creation, viewing, and management system intended as an aid to the pathologist to review and interpret digital images of surgical pathology slides. The system generates digital images that would otherwise be appropriate for manual visualization by conventional light microscopy.

## Special Controls

A whole slide imaging system must comply with the following special controls: (1) Premarket notification submissions must include the following information: (i) The indications for use must specify the tissue specimen that is intended to be used with the whole slide imaging system and the components of the system. (ii) A detailed description of the device and bench testing results at the component level, including for the following, as appropriate: (A) Slide feeder; (B) Light source; (C) Imaging optics: (D)Mechanical scanner movement; (E) Digital imaging sensor; (F) Image processing software; (G)Image composition techniques; (H)Image file formats; (I) Image review manipulation software; (J) Computer environment; (K)Display system. (iii)Detailed bench testing and results at the system level, including for the following, as appropriate: (A)Color reproducibility; (B) Spatial resolution; (C) Focusing test; (D) Whole slide tissue coverage; (E) Stitching error: (F) Turnaround time. (iv) Detailed information demonstrating the performance characteristics of the device, including, as appropriate: (A)Precision to evaluate intra-system and inter-system precision using a comprehensive set of clinical specimens with defined, clinically relevant histologic features from various organ systems and diseases. Multiple whole slide imaging systems, multiple sites, and multiple readers must be included. (B) Reproducibility data to evaluate inter-site variability using a comprehensive set of clinical specimens with defined, clinically relevant histologic features from various organ systems and diseases. Multiple whole slide imaging systems, multiple sites, and multiple readers must be included. (C) Data from a clinical study to demonstrate that viewing, reviewing, and diagnosing digital images of surgical pathology slides prepared from tissue slides using the whole slide imaging system is non-inferior to using an optical microscope. The study should evaluate the difference in major discordance rates between manual digital (MD) and manual optical (MO) modalities when compared to the reference (e.g., main sign-out diagnosis). (D) A detailed human factors engineering process must be used to evaluate the whole slide imaging system user interface(s). (2) Labeling compliant with 21 CFR 809.10(b) must include the following: The intended use statement must include the information described in paragraph (i) (1)(i) of this section, as applicable, and a statement that reads, "It is the responsibility of a qualified pathologist to employ appropriate procedures and safeguards to assure the validity of the interpretation of images obtained using this device." (ii) A description of the technical studies and the summary of results, including those that relate to paragraph (1)(ii) and (1)(iii) of this section, as appropriate. (iii) A description of the performance studies and the summary of results, including those that relate to paragraph (1)(iv) of this section, as appropriate. (iv) A limiting statement that specifies that pathologists should exercise professional judgment in each clinical situation and examine the glass slides by conventional microscopy if there is doubt about the ability to accurately render an interpretation using this device alone.

*Classification.* Class II (special controls). The special controls for this device are:(1) Premarket notification submissions must include the following information:
(i) The indications for use must specify the tissue specimen that is intended to be used with the whole slide imaging system and the components of the system.
(ii) A detailed description of the device and bench testing results at the component level, including for the following, as appropriate:
(A) Slide feeder;
(B) Light source;
(C) Imaging optics;
(D) Mechanical scanner movement;
(E) Digital imaging sensor;
(F) Image processing software;
(G) Image composition techniques;
(H) Image file formats;
(I) Image review manipulation software;
(J) Computer environment; and
(K) Display system.
(iii) Detailed bench testing and results at the system level, including for the following, as appropriate:
(A) Color reproducibility;
(B) Spatial resolution;
(C) Focusing test;
(D) Whole slide tissue coverage;
(E) Stitching error; and
(F) Turnaround time.
(iv) Detailed information demonstrating the performance characteristics of the device, including, as appropriate:
(A) Precision to evaluate intra-system and inter-system precision using a comprehensive set of clinical specimens with defined, clinically relevant histologic features from various organ systems and diseases. Multiple whole slide imaging systems, multiple sites, and multiple readers must be included.
(B) Reproducibility data to evaluate inter-site variability using a comprehensive set of clinical specimens with defined, clinically relevant histologic features from various organ systems and diseases. Multiple whole slide imaging systems, multiple sites, and multiple readers must be included.
(C) Data from a clinical study to demonstrate that viewing, reviewing, and diagnosing digital images of surgical pathology slides prepared from tissue slides using the whole slide imaging system is non-inferior to using an optical microscope. The study should evaluate the difference in major discordance rates between manual digital (MD) and manual optical (MO) modalities when compared to the reference (
*e.g.,* main sign-out diagnosis).(D) A detailed human factor engineering process must be used to evaluate the whole slide imaging system user interface(s).
(2) Labeling compliant with 21 CFR 809.10(b) must include the following:
(i) The intended use statement must include the information described in paragraph (b)(1)(i) of this section, as applicable, and a statement that reads, “It is the responsibility of a qualified pathologist to employ appropriate procedures and safeguards to assure the validity of the interpretation of images obtained using this device.”
(ii) A description of the technical studies and the summary of results, including those that relate to paragraphs (b)(1)(ii) and (iii) of this section, as appropriate.
(iii) A description of the performance studies and the summary of results, including those that relate to paragraph (b)(1)(iv) of this section, as appropriate.
(iv) A limiting statement that specifies that pathologists should exercise professional judgment in each clinical situation and examine the glass slides by conventional microscopy if there is doubt about the ability to accurately render an interpretation using this device alone.

## Predicate Devices

- Hamamatsu NanoZoomer S360MD Slide scanner system ([K233027](/device/K233027.md))
- Aperio GT 450 DX ([K232202](/device/K232202.md))

## Submission Summary (Full Text)

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FDA

U.S. FOOD &amp; DRUG

ADMINISTRATION

# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

## I Background Information:

A 510(k) Number

K252762

B Applicant

Indica Labs, LLC

C Proprietary and Established Names

HALO AP Dx

D Regulatory Information

|  Product Code(s) | Classification | Regulation Section | Panel  |
| --- | --- | --- | --- |
|  QKQ | Class II | 21 CFR 864.3700 - Whole Slide Imaging System | PA - Pathology  |

## II Submission/Device Overview:

A Purpose for Submission:

New device

B Type of Test:

Software only device

## III Intended Use/Indications for Use:

A Intended Use(s):

See Indications for Use below.

B Indication(s) for Use:

Food and Drug Administration

10903 New Hampshire Avenue

Silver Spring, MD 20993-0002

www.fda.gov

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HALO AP Dx is a software only device intended as an aid to the pathologist to review, interpret and manage digital images of scanned surgical pathology slides prepared from formalin-fixed paraffin embedded (FFPE) tissue for the purposes of pathology primary diagnosis. HALO AP Dx is not intended for use with frozen section, cytology, or non-FFPE hematopathology specimens.

It is the responsibility of a qualified pathologist to employ appropriate procedures and safeguards to assure the quality of the images obtained and, where necessary, use conventional light microscopy review when making a diagnostic decision. HALO AP Dx is intended for use with the interoperable components specified in the Table below.

Table: Interoperable Components of HALO AP Dx

|  Scanner Hardware | Scanner Output File Format | Interoperable Displays  |
| --- | --- | --- |
|  Leica Aperio GT 450 DX scanner | SVS | Dell U3223QE
Barco MDPC-8127  |
|   |  DICOM | Dell U3223QE  |
|  Hamamatsu NanoZoomer S360MD Slide scanner | NDPI | Barco MDPC-8127  |

C Special Conditions for Use Statement(s):

Rx - For Prescription Use Only

IV Device/System Characteristics:

A Device Description:

HALO AP Dx, version 2.4 (abbreviated as v2.4), is a browser-based software-only device intended to aid pathology professionals in viewing, manipulating, management, and interpretation of digital pathology whole slide images (WSI) of glass slides obtained from the Hamamatsu Photonics K.K. NanoZoomer S360MD scanner or the Leica Biosystems Imaging, Inc. Aperio GT 450 DX. HALO AP Dx is operated as follows:

1. Image acquisition is performed using the NanoZoomer S360MD scanner or the Aperio GT 450 DX scanner. The operator performs quality control of the digital slides per the instructions of the scanners and additional laboratory specifications to determine if re-scans are necessary.
2. Once image acquisition is complete, the unaltered image is saved in an external image storage location. HALO AP Dx ingests the image, and a copy of image metadata is stored in the subject device's database to improve viewing response times.
3. Depending upon a laboratory's workflow, the scanned images may first be reviewed by histotechnicians to confirm image quality and initiate any re-scans. After review, the histotechnician may modify the case status and make it available to the pathologist.
4. The reading pathologist selects a patient case from a selected worklist within HALO AP Dx whereby the subject device fetches the associated images from external image storage.
5. The reading pathologist uses the subject device to view the images and can perform the following actions, as needed:

a. Zoom and pan the image.
b. Measure distances and areas in the image.
c. Annotate images.

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d. View multiple images side by side in a synchronized fashion.

6. The above steps are repeated as necessary.

After viewing all images belonging to a particular case (patient), the pathologist will make a diagnosis which is documented in another system, such as a Laboratory Information System.

The system specifications for HALO AP Dx are provided in tables 1 - 3 below.

Table 1: Computer Environment / System for Use with HALO AP Dx

|  Component | Requirement  |
| --- | --- |
|  Operating System | Windows 11  |
|  Memory | 16 GB or more  |
|  Processor | Intel Core i7 CPU  |
|  Supported Browsers | Google Chrome version 138 and above Microsoft Edge version 138 and above  |

Table 2: Server System Requirements

|  Server | Operating System | Memory | Processor  |
| --- | --- | --- | --- |
|  Component Server, Processing Node Server, File Monitor Server | Windows Server 2022 Only x64 (64 bit) operating systems are supported | 16 GB or more | 8 CPU cores or more  |
|  Traefik Reverse Proxy | Windows Server 2022 Ubuntu 22.04 | 2GB, per 150 concurrent users | 2 CPU Cores, per 150 concurrent users  |
|  MySQL Server | Windows Server 2022 Ubuntu 22.04 Only x64 (64 bit) operating systems are supported | 16 GB or more | 4 CPU Cores or more  |

Table 3: Server Configurations

|  Component | Specifications  |
| --- | --- |
|  Network Connectivity | 1 Gbps (10 Gbps recommended) LAN connection between services  |
|  Antivirus Software | The following antivirus software has been validated for use with Windows Server: - Microsoft Windows Defender - Trend Micro - Webroot  |

# B Instrument Description Information:

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1. Instrument Name:
HALO AP Dx

2. Specimen Identification:
HALO AP Dx uses digital pathology images obtained from the interoperable scanners of Hematoxylin and Eosin (H&amp;E) stained glass slides. The reading pathologist selects a case (patient) from a worklist (within the device or external to the device) whereby the subject device fetches the associated images from the external image storage. The scanned images are identified based on the previously assigned specimen identifier.

3. Specimen Sampling and Handling:
Specimen sampling and handling are performed upstream and independent of the use of the subject device. Specimen sampling includes biopsy or resection specimens which are processed using histology techniques. The FFPE tissue section is H&amp;E stained. Digital images are then obtained from these glass slides using the interoperable scanners.

4. Calibration:
Not applicable.

5. Quality Control:
The scanning technician should perform quality control of all glass slides following the instructions for the specific staining protocol. Upon scanning, quality control should be performed on all digital slide images following procedures defined by the scanner manufacturer prior to import into HALO AP Dx.

The pathologist should review all images to ensure that all expected slides have been imported by viewing the thumbnails and labels, and manually verifying the tissue specimen, tissue block, and staining information is present. Additional details of the quality control procedures are provided in the device User's Guide and the Implementation Guide.

V Substantial Equivalence Information:

A Predicate Device Name(s):
Aperio GT 450 DX, NanoZoomer S360MD Slide scanner system

B Predicate 510(k) Number(s):
K232202, K233027

C Comparison with Predicate(s):

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| Device & Predicate Device(s): | K241273 | K232202 | K233027 |
| --- | --- | --- | --- |
| Device Trade Name | HALO AP Dx | Aperio GT450X | NanoZoomer S360MD Slide scanner system |
| General Device Characteristic Similarities |
| Intended Use /Indications For Use | HALO AP Dx is a software only device intended as an aid to the pathologist to review, interpret and manage digital images of scanned surgical pathology slides prepared from formalin-fixed paraffin embedded (FFPE) tissue for the purposes of pathology primary diagnosis. HALO AP Dx is not intended for use with frozen section, cytology, or non-FFPE hematopathology specimens. It is the responsibility of a qualified pathologist to employ appropriate procedures and safeguards to assure the quality of the images obtained and, where necessary, use conventional light microscopy review when making a diagnostic decision. HALO AP Dx is intended for use with the interoperable components specified in the Table below. Table: Interoperable components of HALO AP Dx | The Aperio GT 450 DX is an automated digital slide creation and viewing system. The Aperio GT450 DX is intended for in vitro diagnostic use as an aid to the pathologist to review and interpret digital images of surgical pathology slides prepared from formalin-fixed paraffin embedded (FFPE) tissue. The Aperio GT 450 DX is for creation and viewing of digital images of scanned glass slides that would otherwise be appropriate for manual visualization by conventional light microscopy. Aperio GT 450 DX is comprised of the Aperio GT 450 DX scanner, which generates images in the Digital Imaging and Communications in Medicine (DICOM) and in the ScanScope Virtual Slide (SVS) file formats, the Aperio WebViewer DX viewer, and the displays. The Aperio GT 450 DX is intended to be used with the interoperable components specified in Table 1. Table 1: Interoperable components of Aperio GT 450 DX | The NanoZoomer S360MD Slide scanner system (“NanoZoomer System”) is an automated digital slide creation, viewing, and management system. The NanoZoomer System is intended for in vitro diagnostic use as an aid to the pathologist to review and interpret digital images of surgical pathology slides prepared from formalin-fixed paraffin embedded (“FFPE”) tissue. The NanoZoomer System is not intended for use with frozen section, cytology, or non-FFPE hematopathology specimens. The NanoZoomer System comprises the NanoZoomer S360MD Slide scanner, the NZViewMD Software and a compatible display that has been 510(k) cleared for use with the NanoZoomer system or a 510(k)-cleared display that has been assessed in accordance with the Predetermined Change Control Plan (PCCP) for qualifying additional compatible displays. The NanoZoomer System is for creation and viewing of digital images of scanned glass slides that would otherwise be appropriate for manual visualization by conventional light microscopy. It is the responsibility of a qualified pathologist to employ appropriate procedures and safeguards to assure the validity of the interpretation of images obtained using NanoZoomer System |
| Scanner Hardware | Scanner Output file format | Interoperable Displays | Scanner Hardware | Scanner Output file format | Interoperable Viewing Software | Interoperable Displays |
| Leica Aperio GT 450 DX scanner | SVS | Dell U3223QE Barco MDPC-8127 | Aperio Gt 450 DX scanner | SVS | Aperio WebViewer DX | Barco MDPC-8127 Dell UP3017 Dell U3023E Dell U3223QE |
| DICOM | Dell U3223QE | Aperio GT 450 DX scanner | SVS | Sectra Digital Pathology Module (3.3) | Dell U3223QE |
| Hamamatsu NanoZoomer S360MD Slide scanner | NDPI | Barco MDPC-8127 | Aperio GT 450 DX scanner | DICOM | Sectra Digital Pathology Module (3.3) | Dell U3223QE |

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|   |  | appropriate procedures and safeguards to assure the validity of the interpretation of images obtained using the Aperio GT 450 DX. |   |
| --- | --- | --- | --- |
|  Principle of Operation | During review, the pathologist opens the WSI images acquired with the scanner from the network storage, performs further QC, and reviews and interprets the WSI images to make a diagnosis. | The Aperio GT 450 DX is a WSI system. The technician places the slides into the Aperio GT 450 DX scanner. The Aperio GT 450 DX scanner automatically loads the slides, takes the micro images, finds the tissues, and scans the slides. The scanner also automatically performs quality control (QC) and notifies the user of any image quality issue during the image acquisition. The image data is sent to end-user-provided image storage attached to the local network. During the review, the pathologist opens WSI images acquired with the WSI scanner from the image storage, performs further QC, and reads WSI images of the slides to make a diagnosis. | The NanoZoomer S360MD Slide scanner system (“NanoZoomer System”) is an automated digital slide creation, viewing, and management system. The NanoZoomer System is intended for in vitro diagnostic use as an aid to the pathologist to review and interpret digital images of surgical pathology slides prepared from formalin-fixed paraffin embedded (“FFPE”) tissue. The NanoZoomer System is not intended for use with frozen section, cytology, or non-FFPE hematopathology specimens. The system’s embedded image processing software is responsible for image acquisition and the processing of individual tiles prior to image composition or stitching. Hamamatsu’s NZAcquireMD software organizes all WSI tiles into a single NDPi file, which is a proprietary file format. During the review, the pathologist opens the WSI on the NZViewMD software to render a diagnosis.  |
|  Specimen Type | Digitized surgical pathology slides prepared from FFPE tissue | Same | Same  |
|  Type of Software Application | Internet browser-based application | Same | PC-based installed application  |
|  Image Manipulation and Review Functions | Functions for continuous panning and zooming, annotations, distance/area measurements, track visited areas, and image adjustments. | Same | Functions for continuous panning and zooming, annotations, distance/area measurements, track visited areas, export images, discrete Z-axis displacement, and display of diagnostic status of images.  |
|  **General Device Characteristic Differences**  |   |   |   |
|  Device Components | HALO AP Dx viewing software | WSI scanner (Aperio GT450 DX scanner), Image Management System (Aperio WebViewer DX image viewing software), Display | WSI scanner (NanoZoomer S360MD Slide scanner), Image Management System (NZViewMD), Display  |
|  Diagnostic Image File Format | Leica SVS and DICOM, Hamamatsu NDPI | Leica SVS and DICOM | Hamamatsu NDPI  |
|  End User’s Interface | HALO AP Dx | Aperio WebViewer DX for Leica SVS, Sectra Digital Pathology Module (3.3) for Leica SVS and DICOM | NZViewMD  |

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VI Standards/Guidance Documents Referenced:

1. FDA Guidance “Technical Performance Assessment of Digital Pathology Whole Slide Imaging Devices”. April 20, 2016.
2. FDA Guidance “Applying Human Factors and Usability Engineering to Medical Devices”. February 3, 2016.
3. FDA Guidance “Content of Premarket Submissions for Device Software Functions”. June 14, 2023.
4. FDA Guidance “Cybersecurity in Medical Devices: Quality System Considerations and Content of Premarket Submissions”. September 27, 2023.
5. IEC 62304 Edition 1.1 2015-06: Medical device software - Software life cycle processes
6. ISO 14971 Third Edition 2019-12: Medical devices - Application of risk management to medical devices
7. IEC 62366-1 Edition 1.1 2020-06: Medical devices - Part 1: Application of usability engineering to medical devices
8. AAMI TIR45:2012: Guidance on the use of AGILE practices in the development of medical device software

VII Performance Characteristics (if/when applicable):

A Analytical Performance:

1. Precision/Reproducibility: Not applicable
2. Linearity: Not applicable
3. Analytical Specificity/Interference: Not applicable
4. Accuracy (Instrument): Not applicable
5. Carry-Over: Not applicable

B Other Supportive Instrument Performance Characteristics Data:

Technical performance testing was conducted with the subject device, HALO AP Dx as specified below.

1. Bench Testing - Pixelwise comparison test
HALO AP Dx supports multiple file formats, multiple browsers, and multiple displays, constituting various configurations to be tested. Pixel-wise comparison testing to demonstrate

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identical image reproduction was conducted to compare WSIs reproduced by the subject device and the comparators as listed in Table 4 below. The subject device was compared to the predicate device's image review manipulation software (IRMS), as defined in FDA guidance document, "Technical Performance Assessment of Digital Pathology Whole Slide Imaging Devices" dated April 20, 2016) using the quantitative pixel-wise comparison method. The basis for the comparison was the CIEDE2000 color difference equation,  $\Delta E00$ . The devices were tested as operating with the intended components, including the scanner, specific file format, image management systems (subject device with the intended browsers, comparator [predicate device IRMS]) and displays, as specified in the Table 4 below.

For each of the 6 configurations in Table 4 below, the device was tested with multiple slides across multiple regions of interest (ROI) at multiple magnification levels, on multiple displays. A total of  $30\mathrm{H}\&amp;\mathrm{E}$ -stained, FFPE glass slides of normal and tumor tissues from various human anatomical organs were used in the testing. For each configuration, the glass slides were scanned on a corresponding intended scanner to obtain 30 WSIs. For each of the 30 WSIs, 3 ROIs from different locations were selected by qualified personnel to represent various features in the tissue samples. Each ROI was captured at 2 magnification levels (10x, 40x).

The screenshots were captured for each of the intended display while viewing with the subject device and predicate device IRMS. The screenshots were cropped and registered to be pixelwise comparable. The cropped image included most of the pixels in the image except for those in the viewer-specific user interface areas.

For each configuration and each intended display, two sets of images were collected: comparator (predicate device IRMS) and the subject device (HALO AP Dx with the intended browser). Each image set included 180 images that covered all combinations of 30 slides, 3 ROIs and 2 magnification levels. The testing data, including the overview images of the 30 glass slides with annotations of the ROIs, registration/cropping information, and captured images, were provided in the FDA specific format. The above procedure was repeated for each corresponding intended display.

The comparator (predicate device IRMS) image set was used as the reference to compare the subject device image set to determine whether all the 180 image-pairs were identical for each configuration and each intended display. Two images are considered identical if the 95th percentile of the pixelwise differences, computed using the International Commission on Illumination (CIE) color difference metric CIEDE2000 ( $\Delta E_{00}$ ), is less than  $3\Delta E_{00}$ . Testing results showed that the pixelwise differences across all 180 image-pairs per configuration and per intended display were less than  $3\Delta E_{00}$ . The maximum (max), minimum (min), and mean of the 95th percentile  $\Delta E_{00}$  value were reported in Table 4. Testing results demonstrated that WSIs reproduced by HALO AP Dx are identical to images reproduced by the predicate devices.

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Table 4. HALO AP Dx Pixelwise Comparison Testing Results

|  Scanner | Image File Format | Subject Device/ Browser | Comparator (Predicate device IRMS /Browser) | Display | Results  |
| --- | --- | --- | --- | --- | --- |
|  NanoZoomer S360MD Slide scanner | NDPI | HALO AP Dx/Chrome | NZViewMD | Barco MDPC-8127 | max (95th percentile ΔE00) = 2.929 min (95th percentile ΔE00) = 0.703 mean (95th percentile ΔE00) = 1.466  |
|   |   |  HALO AP Dx /Edge | NZViewMD |   | max (95th percentile ΔE00) = 2.939 min (95th percentile ΔE00) = 0.705 mean (95th percentile ΔE00) = 1.457  |
|  Aperio GT450DX scanner | SVS | HALO AP Dx /Chrome | Webviewer | Barco MDPC-8127 | max (95th percentile ΔE00) = 2.69 min (95th percentile ΔE00) = 0.810 mean (95th percentile ΔE00) = 1.396  |
|   |   |   |   |  DELL U3223QE | max (95th percentile ΔE00) = 2.417 min (95th percentile ΔE00) = 0.864 mean (95th percentile ΔE00) = 1.390  |
|   |   |  HALO AP Dx /Edge | Webviewer | Barco MDPC-8127 | max (95th percentile ΔE00) = 2.167 min (95th percentile ΔE00) = 0.807 mean (95th percentile ΔE00) = 1.385  |
|   |   |   |   |  DELL U3223QE | max (95th percentile ΔE00) = 2.211 min (95th percentile ΔE00) = 0.869 mean (95th percentile ΔE00) = 1.384  |
|   |  DICOM | HALO AP Dx /Chrome | Sectra UniView /Chrome | DELL U3223QE | max (95th percentile ΔE00) = 1.928 min (95th percentile ΔE00) = 0.689 mean (95th percentile ΔE00) = 1.411  |
|   |   |  HALO AP Dx /Edge | Sectra UniView /Edge |   | max (95th percentile ΔE00) = 2.014 min (95th percentile ΔE00) = 0.880 mean (95th percentile ΔE00) = 1.406  |

# 2. Turnaround Time

The turnaround time for image opening, panning, and zooming were tested in the subject device when using all the supported browsers (Chrome, Edge) for each image format (NDPI, SVS, DICOM). The acceptance criteria were as follows:

- Average time to open cases shall not exceed 4 seconds.
- Average time to perform zoom operations and fully load all image tiles shall not exceed 3 seconds for the combined operations on any image in any browser.
- Average time to perform single Field of View (FOV) pan operations and fully load all image tiles shall not exceed 3 seconds.
- Average time to perform long-distance FOV pan operations and fully load all image tiles shall not exceed 3 seconds.
- Simulated use scaling up to 30 users viewing 200 images in a simulated pan/zoom routine should not produce median response times above 3 seconds over a time of 8 hours.

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Test results for different scenarios met the test acceptance criteria and showed acceptable turnaround time for the intended use of the subject device.

## 3. Measurement – distance and area

The length and area measurement accuracy of the subject device was tested across multiple magnification levels. An image of a calibration scale slide with known object sizes was used to verify the measurement accuracy. A series of annotations were created to cover different orientations, different magnification levels and all the supported file formats (NDPI, SVS, DICOM) in all the intended browsers (Chrome, Edge). The differences between the actual and reported measurements were calculated for each annotation.

The acceptance criteria were as follows:

- The measurement comparisons shall match a distance within 0.005 mm or an area of 0.001 mm².
- Resolution data is displayed correctly, and no distortion is presented in the image display.
- Annotation measurements will not be distorted at uneven magnification levels or when the user is zooming in and out on the slide image.

The average length measurement difference was less than 0.005 mm, and the average area measurement difference was less than 0.001 mm² when evaluated on scanned slides with objects of known sizes from the NanoZoomer S360MD scanning system and the Aperio GT 450 DX. The resolution data was displayed correctly with no distortion, and the annotation measurements were correct at uneven magnification levels and when zooming in and out. Test results showed that the subject device performed accurate measurements of length and area across multiple magnification settings with respect to its intended use.

## 4. Human Factor (Usability) Testing

Human factors study designed around critical user tasks and use scenarios performed by representative users were conducted for previously cleared HALO AP Dx, version 2.1, in K232833, per FDA’s Guidance on Applying Human Factors and Usability Engineering to Medical Devices (2016). Human factors validation testing is not necessary as the user interface and workflow remain unchanged.

## VIII. Proposed Labeling:

The labeling supports the finding of substantial equivalence for this device.

## IX. Conclusion:

The submitted information in this premarket notification is complete and supports a substantial equivalence decision.

K252762 - Page 10 of 10

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**Source:** [https://fda.innolitics.com/submissions/PA/subpart-d%E2%80%94pathology-instrumentation-and-accessories/QKQ/K252762](https://fda.innolitics.com/submissions/PA/subpart-d%E2%80%94pathology-instrumentation-and-accessories/QKQ/K252762)

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