Q. An 18-year-old female was admitted two days ago for depression, weight gain, and hirsutism. She has struggled in school and social activities recently, and has withdrawn from family and peers. The patient has a history of depression, for which she was previously treated with fluoxetine with limited success. She also has a recent unintentional weight gain of 10 pounds over the past three months. Additionally, the patient has noticed excessive hair growth on her face and abdomen, which has been progressively worsening over the past year. She has no history of diabetes, hypertension, or history of steroid use. The patient is an unmarried college student who lives with her parents. She reports no alcohol or drug use. She lives a sedentary lifestyle and reports poor dietary habits. The patient was admitted by her psychiatrist, who has asked you to evaluate her metabolic complaints. On physical examination, the patient appears uncomfortable and tearful. Her temperature is 37 degrees Celsius (98.7 degrees Fahrenheit), blood pressure is 140/90 mm Hg, heart rate 72/min, and her respiratory rate is 16/min. Evaluation of her neck reveals no cervical lymphadenopathy or thyromegaly. Her lungs are clear to auscultation bilaterally, and her heart is in regular rate and rhythm with no murmurs, rubs, or gallops. You palpate her abdomen and detect no hepatosplenomegaly, masses or tenderness. Linear, irregular, purple and red striations are noted on her abdominal flanks bilaterally (see image), and you also appreciate excessive hair growth on her back. There is no cyanosis, clubbing, or edema noted. Based on her history and physical examination, which of the following tests is LEAST useful at this time in determining her diagnosis?