A 63-year-old female patient complains of profuse sweating and palpitations. She does not report headache or tremor. The patient has a 10-year history of difficult-to-control hypertension and insulin-dependent type 2 diabetes. She also has family history of sudden death in first-degree relatives. She shows some laboratory results which lead the treating physician to order an abdominal computed tomography.

Question:
When evaluating patients with such clinical history, which biochemical testing must precede the imaging study?