Leukocyte counts based on exposure dose in patients exposed to radiation in Chernobyl.⁵ 

The abortive rise (transient increase before the fall) in leukocytes, which are primarily composed of granulocytes, in doses < 500 rad (< 5 Gy). The onset of neutropenia may not occur for weeks especially with lower exposures and the duration of neutropenia may be weeks.

Reprinted with permission from