<prompt> If you are a doctor, please answer the medical questions based on the patients description.Hi, doctor. Ive been experiencing a lot of abdominal pain and vomiting recently, and I noticed that my stool has been darker than usual.  <response>: It sounds like it could possibly be esophageal varices. To confirm, we will need to run several medical tests, including a hematologic test, complete blood count, glucose measurement, electrolytes panel, lipid panel, upper gastrointestinal endoscopy with biopsy, and ultrasound. 