Which examination should be performed first in a sequence of five specific studies?

In the context of a sequence of five specific studies, fiberoptic studies should generally be performed first due to their non-invasive nature and the fact that they provide real-time visualization of the gastrointestinal tract. Fiberoptic procedures, such as endoscopy, allow for direct inspection and potential intervention without needing preparatory bowel preparations that other studies might require.

For example, performing a fiberoptic study can help identify abnormalities that may be critical for deciding the sequence of imaging studies or interventions needed afterward. If significant findings are also noted during the fiberoptic examination, it may alter the course of treatment or further diagnostic evaluations.

The other examination types typically involve more invasive preparation, such as the upper and lower gastrointestinal series, which requires fasting and bowel cleansing, and computed tomography studies, which might necessitate contrast materials that can have an impact on the digestive system's state. Starting with fiberoptic studies helps ensure that any necessary follow-up imaging or treatment can occur without unnecessary delays or complications related to contrasts or bowel preparations seen in the other studies.