Agranulocytosis is something than can happen with many medications . It is very serious because it can be deadly however there are times when risk vs benefits are considered and the outcome is strict monitoring.

Clozaril is an excellent example. It is a very effective antipsychotic medication with a risk of agranulocytosis so it is mandated that the patient is tested weekly, then monthly to monitor. Pharmacies won't even fill the medication if they haven't verified the patients blood work. It is so effective in fact that there are instances where additional medications to increase the wbcs are added in an effort to keep the patient on Clozaril.

The other thing to consider is there are variants to wbc levels. With benign ethnic neutropenia people have natural, harmless low levels that should be considered when interpreting labs.

Bottom line for me: Its definitely something to be aware of and monitor but not necessarily a need to call 911 just yet.