A 46-year-old G0P0 female presents to her primary care provi…
A 46-year-old G0P0 female presents to her primary care provider with insomnia. Over the past 3 months, she has experienced insomnia nearly every night, which is affecting her workplace performance. When she tries to sleep, she reports feels a “crawling” sensation deep inside her calves. She feels better when she repositions her legs, but the sensation always returns. She has no known medical problems and denies any current prescription or over the counter medications. Her menstrual cycles are described as “regular, heavy, and stable” over the past 5 years. Her last menstrual period was 3 weeks ago. She does not smoke or drink alcohol. Vital signs: T 99.6°F, BP 120/70 mmHg, HR 80/min, and RR 18/min. On physical exam, her calves are non-tender to palpation. Sensation is intact to light touch in both feet. Ankle reflexes are 2+. Based on the suspected diagnosis, measurement of which of the following would be most appropriate to obtain in this patient?