Specimen: 50 mL (10 mL min.) aliquot of random urine. Add 50% HCl drop by drop to bring the pH between 1–2. Do not use concentrated HCl. Ship refrigerated or frozen. Patient should strictly avoid Theophylline, chocolate, vanilla, banana, alcoholic beverages, tea/coffee, tobacco and strenuous exercise at least 72 hrs before and during specimen collection....



