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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

About Us

This site is maintained by Perceptive Instruments, industry-leading experts in image analysis for the comet assay.

We regularly attend comet assay workshops and contribute to the debate towards regulatory acceptance of the assay.

About Comet Assay IV

Comet Assay IV is the world's fastest, most consistent comet assay scoring system.

For our full range of products, head over to www.perceptive.co.uk