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Comet Assay IV


Live video measurement system for the comet assay

  • Single click automatic scoring
  • Accurate, repeatable results
  • Tail % DNA, tail moment, tail length and more
  • Integrated hedgehog counter
  • Graph and chart your comet data
  • GLP compliance, auditing and user control

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Comet Assay IV is a live video imaging system designed for those seeking fast, accurate and reproducible comet slide scoring. Scoring cells with Comet Assay IV is a uniquely effortless process: simply use the mouse to click once on each cell. Typically, you can score 50 cells on a slide within two minutes.


“I have been using the Comet Assay IV software – it is great! During my software validation, I realized how much easier and precise it is compared to our old software. It makes analyzing the comet slides more enjoyable” Scientist, Medical research centre, USA


How it works

Score comets from live video

Using a high resolution digital camera attached to your microscope, Comet Assay IV transfers a live video picture to your screen. Any refocusing or stage movements performed at the microscope level are shown live on screen without any lag or delay.

Comet Assay IV introduces a revolutionary automatic scoring method in which a single click on a comet initiates & completes the entire measurement cycle, including background correction, determination of head and tail regions and computation of all parameters.

With Comet Assay IV, you simply click once on each comet you wish to score. This has productivity and reproducibility advantages over manual framing methods that require users to position a measurement frame around each individual cell. Once all the comets within in a field of view have been scored, you can use your microscope’s stage controls to find the next set of cells to be scored.

Eliminate user subjectivity and bias

Comet Assay IV’s scoring method does not require the configuration of any adjustable settings, thereby eliminating all subjectivity from the scoring process. Comet Assay IV automatically compensates for slides with uneven backgrounds or varying levels of brightness, ensuring comparable results across a wide range of slides; even highly damaged ‘hedgehog’ comets can be accurately and consistently measured. In addition, to further remove user bias, measurements for each slide are viewable within a scrollable results window, which can be hidden entirely for those wishing to score blind.

Graph and report data

Having obtained your results, you can create graphs, tabulate data and calculate statistics using  the Spreadsheet Generator, which is included free with every Comet Assay IV system. The Spreadsheet Generator is an application built in Excel for drawing graphs, tabulating data and calculating statistics from your Comet Assay IV results. Because it is built in Excel, it can easily be customised using any of Excel’s standard functions and features.

Integrate slide coding, data acquisition, reporting and statistics

Comet Assay IV links directly to Cyto Study Manager which manages slide coding, labelling and reporting without the need for transcription or copying & pasting data. See the Cyto Study Manager product page for more information.

Reasons to buy

Used by the experts

Validated by labs worldwide, Comet Assay IV has an established user base including many of the world’s top pharmaceutical and research organisations. It is used by the majority of labs involved in the JaCVAM international comet validation study, and within other global comet assay projects, such as COMNET. At the recent International Comet Assay Workshop, nearly two thirds of all oral presentations were delivered by current users of Comet Assay systems from Perceptive Instruments.

Faster study turnaround

Our users tell us that they are able to score 100 cells from a typical comet assay slide within five minutes. This means all the scoring for a study can be completed in a few hours rather than several days. Using the included Excel Spreadsheet Generator, graphs, charts and tables can be generated automatically. With unrivalled speed and reproducibility, Comet Assay IV is the de facto comet assay scoring system used for genetoxicity testing.

Increase traceability of data

Comet Assay IV has been designed with reference to the OECD and S2(R1) guidelines. It is fully compliant with the principles of Good Laboratory Practise (GLP) and the FDA 21 CFR part 11 rule on electronic signatures.

All actions which are carried out within Comet Assay IV, such as creating, editing and deleting data, are recorded within an audit trail. Original data are never obscured; where a data change is made, the old and new values are visible along with any reasons given for the change.

Supported by the experts

When you purchase Comet Assay IV, you will receive a comprehensive support package including software updates and unlimited support over phone, email and via screen sharing tools. We will help you install and configure your system and provide training and validation assistance to ensure that you get the best from Comet Assay IV.

Regulatory compliance

Audit trails

Comet Assay IV is designed to conform to international GLPs and other regulatory requirements. Every action taken within the program can be used to prompt a user to give a reason for a change (e.g. when editing or deleting a measurement), or to force the user to apply unique electronic signatures to confirm their identity (e.g. when saving data).

The audit trail records every action taken within the program including all data. Where changes to data are made, the original and new values are recorded. The audit trail is encoded, so that only users with the correct permissions can view it.

User access and 21 CFR compliance

Combining Comet Assay IV with our user access management program, System Access Manager, strengthens your case for compliance by managing and maintaining user access in line with the FDA 21 CFR part 11 rule on Electronic Records and Electronic Signatures.

Individual users are assigned unique user IDs and granted a choice of access levels to Comet Assay IV. The system manages user access via a wide range of password rules including expiry, length, use of characters and numbers and more.


We are on hand to help with all your regulatory compliance documentation needs.  An IQ can be provided.

Study management and regulatory testing

Comet Assay IV connects seamlessly to Cyto Study Manager for those running comet studies to regulatory standards. Cyto Study Manager integrates all your data acquisition, reporting and management needs into one software package.

Automatic sample coding saves time and ensures data integrity. All your reports can be generated from the within the system and automatically combined into your final study report. Studies can be approved, signed and archived. Reports can include sample coding/decoding information, results tables, historical data ranges, audit information and more.

Because all of this is achieved within one system, there is no risk of transcription errors, no import/export, no file transfers and no copy and paste.

Technical specification


Click&ScoreTM – a single click on a comet initiates & completes the entire measurement cycle. Measurement performed & results returned instantly. Ability to score ‘blind’ if desired. Comets can be scored live or from saved images.

Study Scope

No constrains on study scope or layout. Any number of cells per slide. Configurable message appears when set number of comets have been scored.


With Click&Score, users can score a typical slide in two minutes. Individual cells are scored instantly.

Help & Tutorials

In-depth help system includes tutorials and comprehensive guides on system setup and configuration.


Unlimited number of system configurations can be created for different study requirements. Configurations include setup information on how the system operates in a specific situation.


Unlimited number of calibrations can be saved for different microscope objectives.


Each system configuration can be configured with any number of headings for study ID, slide ID, dose etc. Configurable as revert to blank or revert to previous entry.

Electronic Records & Signatures

Compatible with the System Access Manager for compliance with FDA 21 CFR Part 11 Final Rule on Electronic Records & Electronic Signature.

Audit Trails

Encoded audit trail files automatically record all system activity including settings, measurement data and edits. Audit trail data can also be sent directly to an Oracle database.

User Levels

Supervisor & User levels.

User Access Rights

Supervisors may lock any of the menus, or selected options within them, to deny Users access to particular functions.


Comprehensively tested and validated in accordance with our Quality Management System which is approved to ISO 9001:2008 incorporating ISO 90003. Validation and project documentation supplied with system.


Full pseudocolour overlay and onscreen gamma correction to help users visualise cells.

Data Processing & Transfer

Powerful new macros allow users to compare data across dose ranges. Macros include statistics, log transforms & frequency distribution graphs. Configurable data transfer to Oracle database.


All core Comet assay measurement parameters: Tail % intensity, Head % intensity, Olive tail moment, Tail length, Head length, Tail moment, Total area, Mean grey level, Width, Total intensity. Also allows a tally of hedgehog cells to be created.


Interactive editing of head, middle of head and tail positions for badly damaged cells.

Video Picture

High resolution monochrome FireWire CCD camera provides live video at 25 frames per second.

Background Correction

Fully automatic adaptive background correction that requires no configuration of settings.

Invert Video

Invert video option for scoring silver stained slides.

Image functions

Freeze image, Go live, Save to file, Load from file. Range of image loading functions including compatibility with TWAIN devices. Audit image save & retrieve saves images with measurement frame position, allowing measurements to be reproduced at a later date.

Minimum Specification

Microsoft Windows XP, 7 or 8. Microsoft Office 2002 or later. Oracle 10g, 11g or 12c if you intend to connect to a database. One free FireWire port, or one free PCIe slot for FireWire expansion board.

Compare packages

Comet Assay IV is available in a range of packages:

  • Comet Assay IV Lite offers entry level functionality at a low price.
  • Comet Assay IV offers a more complete solution for those wishing to use live video images, either from their own camera* or one supplied by us.
  • Comet Assay IV GLP Suite is a suite of products specifically designed for those working within a regulatory environment.
Comet Assay IV Lite Comet Assay IV Comet Assay IV GLP Suite
Score comets from live video input yes yes
High sensitivity digital camera included yes yes
Connect to third-party cameras* yes yes
Score comets from stored image files yes yes yes
Score comets in a single click with Click&Score yes yes yes
Save comet data to Excel or Oracle yes yes yes
Perform advanced data processing with the Spreadsheet Generator yes yes yes
Automatically save measured images yes yes yes
View and recreate measurements from archived images yes yes yes
Batch export study data to Excel yes
Filter, sort and search data yes
Approve and reject data using electronic signatures yes
Securely archive data in accordance with OECD guidelines yes
View and extract results and audit trail data from Oracle yes
Uniquely identify individual users yes
Manage users in accordance with GLP and FDA 21 CFR Part 11 yes
Track and automatically record all user activity yes
Record all unauthorised login attempts yes

*Compatible with Leica, QImaging, AVT and Basler cameras.

Case studies

For an extensive catalogue of Comet Assay IV case studies, applications and investigations, please visit www.scorecomets.com, our website dedicated to the comet assay. There, we routinely add new articles detailing the very latest publications and investigations conducted using Comet Assay IV. If you would like your publication to be showcased on our site, please contact us using the form at the bottom of this page.


Diet and health

We have showcased stories on foods with health benefits, such as grape seeds, kiwi fruit and green vegetables.


There have been publications on environmental and biomonitoring studies, such as the occupational exposure of pottery workers and potential genotoxity caused by extreme exercising.

Comet assay conferences

We love seeing Comet Assay IV data on posters and in presentations at GeneTox conferences. At the recent International Comet Assay Workshop, nearly two thirds of all oral presentations were delivered by current users of Comet Assay systems from Perceptive Instruments.

DNA repair methodology

The comet assay can be used to measure DNA damage and repair mechanisms, here we detail one group who are using the earthworm cells for this application.

Regulatory testing

Validated by labs worldwide, Comet Assay IV has an established user base including many of the world’s top pharmaceutical and research organisations. It is used by the majority of labs involved in the JaCVAM international comet validation study, and within other global comet assay projects, such as COMNET.

Particles and nanoparticles

In addition, we have written reports on the use of Comet Assay IV in nanoparticle research and chemical exposure, such as formaldehyde.

Dedicated comet assay website

Remember to visit www.scorecomets.com for news on the latest research conducted using Comet Assay IV.


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