Which central venous access site is preferred in an adult with normal kidney function to reduce the risk for central line-associated bloodstream infection?

The 82-year-old patient presents to the emergency department with chest pain that started four hours ago. Vascular access is a challenge and the nurse is only able to draw enough blood for one test. The nurse sends the sample to the lab for which test?

The nurse is taking care of a patient with symptoms concerning for Cushing’s syndrome/disease, namely moon facies, acanthosis nigricans, hair loss, thinning of skin, weight gain, hyperglycemia, hypertension, and osteoporosis. Initial diagnostic tests found the patient’s Cushing syndrome to be ACTH-dependent. Which of the following diagnostic tests would best differentiate between an ectopic ACTH-producing source versus a pituitary source?