Two methods of screening for successful gene editing would be by PCR or the use of a reporter gene.
PCR can be used to amplify a region of DNA that will provide identification of whether a gene has been inserted or removed. This can be done by completing PCR with the correct primers, before resolving the amplicon lengths by agarose gel electrophoresis.
Using a reporter gene can be faster, especially where fluorescence is used. Green fluorescent protein (GFP) is a commonly used reporter, producing a green colour when gene editing has been successful and transillumination by UV light. This method does require the reporter gene to be expressed by the transformant, which may be difficult if a gene with a low expression level is used. Brighter fluorescent proteins could be used, such as vsfGFP, which is able to produce a green glow in normal room lighting (and thus a stronger green glow on UV illumination