A subject would not experience _____ following a dose high enough to cause CNS syndrome.

A subject would not experience hematologic syndrome following a dose high enough to cause Central Nervous System (CNS) syndrome because CNS syndrome is characterized by immediate and severe effects on the central nervous system due to high levels of radiation exposure. At such high doses, the damage to the CNS can lead to rapid onset of neurological symptoms that overshadow other potential effects.

Gastrointestinal syndrome typically manifests at lower doses, but when an individual experiences CNS syndrome, it indicates a level of radiation exposure where the likelihood of gastrointestinal symptoms diminishes significantly. In this context, prodromal syndrome, which includes initial signs like nausea and vomiting, would still occur, but hematologic syndrome, which involves more gradual effects on blood cell production, would not emerge in the presence of lethal CNS damage.

Therefore, the primary reason hematologic syndrome is excluded is due to the acute and overwhelming nature of CNS syndrome, which impacts the body's systems in a way that precludes the development of hematologic effects.