A patient is admitted to the medical unit for evaluation of headaches, epigastric pain that is relieved by food, anorexia, nausea and vomiting, and periods of both constipation and diarrhea. The physician orders several diagnostic tests. The nurse knows it is MOST important to schedule which of the following tests FIRST?

1. Upper GI series.
2. Small bowel series.
3. Lower GI series.
4. Lumbar puncture.

Lower GI series

Explanation:

It is a radiographic test that reveals the large intestine along with the rectum, sigmoid, colon, ileocecal valve. When a test for both upper and lower GI series is asked to be carried out, barium is given to the patient via the rectal catheter with an inflatable balloon.

Note that when such test is to be carried out, the lower GI series test must be done first so that the barium from the upper GI will not move down to the GI tract because it will affect the final result of the lower GI series