system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 23-year-old female presents to the emergency department with right lower abdominal pain that began suddenly one hour ago. She is writhing in discomfort and has vomited twice since arrival. She has no chronic medical conditions, but states she has had chlamydia two or three times in the past. Her abdomen is firm, and she is guarding. Pelvic exam reveals blood pooling in the vagina and right adnexal tenderness. Her last menstrual period was 7 weeks ago. A pregnancy test is positive.

Which of the following is an appropriate next step in diagnosis?
assistant
Transvaginal ultrasound