The comet assay, or single-cell gel electrophoresis (SCGE), is
a sensitive, rapid, relatively simple and inexpensive method for
detecting DNA strand breaks in individual cells. It is used in
a broad variety of applications and as a tool to investigate DNA
damage and repair. The sensitivity and specificity of the assay
are greatly enhanced if the DNA incubated with an enzyme,
which recognizes a specific kind of DNA damage. This damage
induced by oxidative stress plays a pivotal role in many diseases
and in aging. This article is a critical review of the possible
application of the comet assay in some pathological states in
clinical practice. Most of the studies relate to evaluating the
response of an organism to chemotherapy or radiotherapy with
statistically significant evidence of DNA damage in patients. Other
useful applications have been demonstrated for patients with
heart or neurodegenerative diseases. Only a few studies have
been published on the use of this method in critically ill patients,
although its use would be appropriate. There are also other
scenarios where the comet assay could prove to be very useful in
the future, such as in predicting the likelihood of certain
pathological conditions.