30 mL aliquot

4 mL aliquot (Note: This volume does not allow for repeat testing.)

Brown urine container with 30 mL 6N HCl preservative. Caution: Strong acid. May cause skin burns.

Instruct the patient to void at 8 a.m. and discard the specimen. Preservative must be added to the container prior to the start of collection. Then collect all urine including the final specimen voided at the end of the 24-hour collection period (i.e., 8 a.m. the next morning). Label container. Keep collection on ice. Measure and record the total urine volume on the test request form. Remove 20 mL aliquot. pH should be <5.

Avoid patient stress. Many drugs (reserpine and α-methyldopa, levodopa, monoamine oxidase inhibitors, and sympathomimetic amines) may interfere and should be discontinued two weeks prior to specimen collection. Nose drops, sinus and cough medicines, bronchodilators and appetite suppressants, α2-agonists, calcium channel blockers, converting enzyme inhibitors, bromocriptine, phenothiazine, tricyclic antidepressants, α- and β-blockers, and labetalol may interfere. Mandelamine® interferes, but thiazides do not. Caffeine products should be avoided before and during collection. The patient should not be subjected to hypoglycemia or exertion. Increased intracranial pressure and clonidine withdrawal can cause false-positive results.

Refrigerate during and after collection.

Specimen with no preservative; original container with pH >5