Review Question - QID 105212

A 29-year-old G1P0 woman at 23 weeks of gestation presents to the emergency department for left flank pain migrating to the groin. The pain is sharp and associated with nausea and vomiting. She also endorses urinary frequency, but denies vaginal discharge. There have been no complications in her pregnancy and she has received all routine prenatal care. She has no known medical problems and takes a multivitamin. She does not smoke cigarettes and denies alcohol or drug use. Her temperature is 98.6°F (37.0°C), blood pressure is 114/70 mmHg, pulse is 90/min, and respirations are 16/min. Her abdominal exam is remarkable for no guarding or tenderness. She also has tenderness to palpation of the left flank. Blood is visible on inspection of the perineal area. Results of a urinalysis are shown below:

Urine Color: Yellow
pH: 7.1
Specific gravity: 1.010
Blood: 3+
Bilirubin: Negative
Glucose: Negative
Ketones: Negative
Protein: Negative
Nitrite: Negative
Leukocyte esterase: Negative
Red blood cells: Many

Which of the following is the most appropriate next step in management?