When scheduling diagnostic studies, which should be done last?

In the context of scheduling diagnostic studies, the barium enema is typically done last due to the nature of its preparation and the potential impact on subsequent imaging studies. A barium enema involves the introduction of a contrast agent (barium) into the colon to enhance imaging. Because barium can remain within the gastrointestinal tract and may obscure or impact the results of other studies, it is prudent to schedule this test after other imaging modalities that might also involve the digestive system.

Other imaging procedures, such as ultrasound, colonoscopy, and computed tomography, can often be performed without the complication of residual contrast dye affecting results. Scheduling these first allows for clear imaging and reduces the risk of diagnostic inaccuracies due to overlapping preparation requirements. Hence, barium enema as the last study ensures that it does not interfere with any prior diagnostic procedures.