The aim of this clinical trial is to investigate whether single-use gastroscopes perform comparably to reusable gastroscopes when used in an endoscopy unit during a period of reduced endoscope reprocessing capacity.

The main question the study aims to answer is:

- How do endoscopists evaluate the performance of single-use gastroscopes compared with reusable gastroscopes in elective and subacute patients undergoing gastroscopy in the endoscopy unit?

Researchers will compare single-use and reusable gastroscopes to determine whether they provide comparable clinical performance. In addition, the study will evaluate the economic consequences of temporarily implementing single-use gastroscopes during a period of reduced reprocessing capacity, as well as compare selected clinical outcomes, including technical success, procedural complications, and the frequency of endoscopic findings.

Participants undergoing gastroscopy during the first study period will be examined using a single-use gastroscope. Participants undergoing gastroscopy during the second study period will be examined using a reusable gastroscope.