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Troubleshooting guide

Sample Preparation

Image Acquisition

  • The image is not obtainable
    Possible Cause

    There are many factors which need to be correct to ensure the comets can be analysed, including but not limited to:

    1) A correctly optimised microscope
    2) Correct illumination and filters
    3) A suitable adapter to connect the camera to the microscope
    4) Microscope camera port not set to send image to the camera


    It is essential to maintain a regular service schedule for your microscope and lamp. Read our comet assay microscopy guide (see menu on right) for more information.

  • No, or poorly visible, comets are observed

    Insufficient staining


    Increase staining time or concentration of DNA stain. As far as Comet Assay IV is concerned, any stain is acceptable. Although the majority of our customers use one of the following fluorochromes for their comet slides: Ethidium bromide, Propidium iodide, SYBR Green or SYBR Gold. Regardless of the stain used, there are some important factors to take into account. Read our comet assay microscopy guide (see menu on right) for more information.

Poor Image Quality

LMAgarose = Low melting point agarose
NMAgarose = Normal melting point agarose


We are using the Comet Assay IV a lot (and our use is increasing). It's working very well.

Professor, Children's Research Hospital, USA

Thanks for your attention and great service. I am so glad that we have Comet IV.

Study Director, Contract Research Organisation, USA

...and the system is running great.

Medical Researcher, Cancer Research Institute, USA

We started using Comet Assay IV and it works well...

Researcher, Nuclear Agency, France

We are very happy with everything, it is easy to work with your software.

Senior Scientist, National Health Institute, Portugal

Comet Assay IV software is in use. Currently our comet analysis is based on tail moment measurement and I must say that everything works properly.

Researcher, Cancer Research Institute, Slovakia

We are impressed indeed! It has saved us quite a lot of time and pains.

Director, Toxicology Research Centre, Spain

I love the software. Keep up the good work over there.

Study Director, Contract Research Organisation, USA

We have installed the software and are using it without any problem. It's really simple! My PhD students are very happy with it.

Professor, University, Spain

The system was set up last month, and so far it works very well. Both my boss and I are very satisfied with it and like it very much.

Researcher, University Hospital, Germany

...we are "happy users" of the software

Senior Researcher, Risk Assessment Institute, Germany

We have had no problems so far, and we are very pleased with the system.

Senior Researcher, Public Health Agency, Finland

Yes, it is very useful and we are in the process of writing a paper also from the data derived from Comet Assay IV.

Assistant Professor, University, USA

It is, indeed, much quicker than the old image analysis system that we had. We are very pleased with it.

Senior Researcher, Public Health Agency, Finland

We are really very happy with the comet analysis system.

Research Scientist, University, Austria

Everything has gone very well with the system and we are very pleased with it.

Professor, University, UK

...Everything is fine with the Comet Assay IV system...and I'm pretty happy about this new software with just clicking on the cells instead of drawing a frame around them

Researcher, Cancer Research Organisation, UK

Excellent, perfectly straightforward.

Scientist, University, UK

Perfect and very clear installation and training!

Researcher, Contract Testing Laboratory, Europe

We have just recently utilized the system and are extremely pleased.

Assistant Professor, University, USA

I don't have any questions about the software as it has worked quite well for us...so far we are very happy with the software.

Research Scientist, University, Australia

Perfect and very clear installation and training.

Study Director, Contract Research Organisation, Europe

We're now using the software and it works great. It has cut our time for comets by at least half.

Post Doctoral Fellow, National Institute of Health, USA

...have been using it now for a couple of weeks and it seems to be working great. Very user friendly - I love it as does my intern!

Staff Chemist, Marine Laboratory, USA

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

The system is up and running. Everybody is impressed with the speed of scoring slides.

Researcher, University, South Africa

The current Comet Assay IV system works without any trouble…we are pleased with the system.

Scientist, Chemical Company, Japan

Just to let you know we have started the validation study for Comet Assay IV and it has been going very well! We ran a comet assay last week and scored the slides with no problems at all. I am very pleased with the system and it will certainly make a difference when we run some comet studies this year!

Study Director, Food & Household Products Company, UK

Total change in our lab since you came (with Comet Assay IV of course...)! thanks... :-)

Postgraduate Researcher, University, France

Everything has gone very well with the system and we are very pleased with it.

Scientist, University, UK

Excellent, the training was very helpful and specific to in-house technicalities.

Lecturer, University, UK

So it's working out fine and we're very happy!

Toxicologist, Health Agency, Canada

The Comet Assay IV system we already installed and is working perfectly.

Scientist, Environmental Institute, Norway

The system is working great.

Senior Research Scientist, Cancer Research Institute, UK

So far, I'm very happy with the system.

Research Lecturer, University, UK

It's an amazing program! Really useful!

Research Scientist, University, Brazil

We have found the Comet Assay IV software very useful and convenient.

Research Scientist, Food Safety Agency, France

It is actually working great.

Professor, University, USA

The installation was quick and all the details were described and easily understandable for the technicians.

Head of Department, Global Chemical Company, Germany

All is going well and the more I use the software the more I love the way it's so simple and intuitive...the comet software is running well and in increasing use.

Scientist, University, UK

We are very satisfied with your software.

Scientist, Cancer Research Institute, Slovakia