What is the laboratory assistant's first response to a needle stick injury?

The laboratory assistant's first response to a needle stick injury is to apply pressure to stop the bleeding. This immediate action is crucial as it helps to control any bleeding that may occur from the puncture site. After applying pressure, it is important to clean the wound appropriately and follow the facility's protocols for reporting and managing such injuries.

While the other options address significant steps that should be taken after an initial response, the immediate focus needs to be on addressing the injury itself to prevent further complications. Visiting a hospital emergency room, reporting the incident, or decontaminating the site are all vital follow-up actions but are not the very first immediate response that should occur in the event of a needle stick injury.