彗星实验（英语：comet assay），又称作单细胞凝胶电泳实验（英语：Single Cell Gel Electrophoresis assay，SCGE）是一种在单个真核细胞水平上检测DNA损伤的实验技术。彗星实验最初由Östling和Johansson在1984年发明，此后由 Singh等在1988年改进，此后成为了间的DNA损伤与修复、遗传毒性生物监测的最常用的标准实验技术。It involves the encapsulation of cells in a low-melting-point agarose suspension, lysis of the cells in neutral or alkaline (pH>13) conditions, and electrophoresis of the suspended lysed cells. The term "comet" refers to the pattern of DNA migration through the electrophoresis gel, which often resembles a comet.

The Single Cell Gel Electrophoresis assay (SCGE, also known as comet assay) is an uncomplicated and sensitive technique for the detection of DNA damage at the level of the individual eukaryotic cell. It was first developed by Östling & Johansson in 1984 and later modified by Singh et al. in 1988. It has since increased in popularity as a standard technique for evaluation of DNA damage/repair, biomonitoring and genotoxicity testing. It involves the encapsulation of cells in a low-melting-point agarose suspension, lysis of the cells in neutral or alkaline (pH>13) conditions, and electrophoresis of the suspended lysed cells. The term "comet" refers to the pattern of DNA migration through the electrophoresis gel, which often resembles a comet.