Amy is 23 years old and presents with a 4 day history of left sided flank pain and dysuria. It is stabbing in nature and there are no obvious relieving or aggravating factors. Paracetamol has not helped the pain. She is known to have recurrent Urinary Tract Infections (UTIs) but feels the pain is different to normal. She is in a long-term relationship and feels there is no risk of sexual transmitted infections.
On examination she is apyrexial with normal observations, and abdominal examination reveals tenderness in the left flank area. Urine dipstick is positive for nitrites.
What is the single most appropriate next step for this patient?