50 ML (10 ML MIN.) ALIQUOT OF 24-HOUR URINE. COLLECT URINE WITH APPROPRIATE VOLUME OF 50% HCL TO MAINTAIN PH BETWEEN 1-2. DO NOT USE CONCENTRATED HCL. RECORD 24 HOUR VOLUME ON TEST REQUEST FORM AND URINE CONTAINER. SHIP REFRIGERATED OR FROZEN. PATIENT SHOULD STRICTLY AVOID ALPHA-ONE BLOCKERS, AMINOPHYLLINE, AMPHETAMINES, AMPICILLIN, BETA-BLOCKERS, EPHEDRINE, IMIPRAMINE, METHYLDOPA, MAO INHIBITORS, NICOTINE, PHENACETIN, PHENOTHIAZINE, THEOPHYLLINE, VASODILATORS, ASPIRIN, PAS, ALPHA-2 AGONISTS, BROMOCRIPTINE, CALCIUM CHANNEL BLOCKERS ( LONG TERM USE), CLOFIBRATE, PROPRANOLOL, PENICILLIN, RESERPINE, THYROXINE, ALPHA-METHYLDOPA, ISOPROTERENOL, LABETALOL, MANDELAMINE, PARACETAMOL, CIMETIDINE, METOCLOPRAMIDE, VIGOROUS EXERCISE, ALCOHOLIC BEVERAGES, TEA/COFFEE AND TOBACCO AT LEAST 72 HOURS BEFORE AND DURING SPECIMEN COLLECTION.