It should moreover be noted that effects can occur in human cells exposed to relatively high levels of radiation. These effects can be detected through specialized bioassay specimens, such as some haematological and cytogenic sampling. They may be used as biological indicators of the exposure and can help to identify and even quantify high individual exposures to radia­tion, such as those occurring in accidents. However, the presence of biologi­cal indicators of exposure does not necessarily imply that the individual had experienced or would experience health effects that could be attributed to radiation.