Methods and compositions for direct detection of DNA damage

The present invention is a method for detecting the extent of DNA damage in a subject suspected of having DNA damage wherein the damage results in the formation of aldehyde moieties in DNA comprising, obtaining a DNA sample from the subject, combining the DNA sample with a fluorescent, chromogenic, pro-fluorescent or pro-chromogenic hydrazine compound to from a fluorescent DNA, detecting the presence of the fluorescent DNA by monitoring the fluorescent emission and quantitating the fluorescent emission thereby determining the extent of DNA damage in the subject.