A 65-year-old male was diagnosed with neuro-cardiogenic syncope. Hutt tilt test was positive. He is under treatment with metoprolol. He has been diagnosed to have hypertension 3 years back. Well controlled on telmisartan.

Again he had syncope.Recent Holter test is normal, echocardiography and ECG is normal, but the blood pressure is not going above 110/70 even without medications. What are the indications of doing urinary catecholamine in this patient? What precautions should be taken?