A patient visits the doctor's office with abdominal pain of two days' duration. Medical history is significant for tonsillectomy and hypertension. The patient denies alcohol and drug abuse. The rectal examination confirms heme-negative stool. Impression: Abdominal pain. Which of the following items represents a symptom?

A. Abdominal pain
B. Tonsillectomy
C. Heme-negative stool
D. Hypertension

To determine which of the items represents a symptom, we need to understand what a symptom is. A symptom is a subjective indication of a disease or condition experienced by the patient themselves.

Let's go through the options one by one:

A. Abdominal pain: This is the presenting complaint mentioned in the scenario. It is a subjective sensation experienced by the patient, so it is a symptom.

B. Tonsillectomy: Tonsillectomy is a surgical procedure to remove the tonsils. It is not a symptom; it is a part of the patient's medical history.

C. Heme-negative stool: Heme-negative stool refers to the absence of blood in the stool. It is a finding obtained during the rectal examination and not a subjective sensation experienced by the patient. Therefore, it is not a symptom.

D. Hypertension: Hypertension is a medical condition characterized by high blood pressure. It is not a symptom; it is a diagnosed medical condition.

So, the correct answer is A. Abdominal pain.