This patient is suffering from acute radiation syndrome. The rapid onset of his gastrointestinal symptoms suggests a life-threatening dose of radiation. In acute radiation sickness, the earlier the onset of this prodromal phase, the greater the likely exposure. The most commonly used method of estimating dose exposure and prognosis is the Andrews lymphocyte depletion curves, which examines the level of lymphocyte decline over 48 hours.
Acute radiation syndrome is often accompanied by a hematopoietic syndrome with pancytopenia, infection, and hemorrhage commonly occurring. However, it is the lymphocyte count at 48 hours that best predicts the patient’s course.
Measuring iodine levels (A) has no prognostic value. Monocytes (C) and platelets (D) typically decline over the course of weeks.
Rella J: Radiation, in Flomenbaum NE, Goldfrank LR, Hoffman RS, et al., (eds): Goldfrank’s Toxicologic Emergencies, ed 8. New York, The McGraw-Hill Companies Inc., 2006, (Ch) 128:p 1803-1816
Goans, Ronald E., Holloway, Elizabeth C., Berger, Mary Ellen, and Ricks, Robert C. "Early Dose Assessment Following Severe Radiation Accidents," Health Physics 72(4):1997