Catecholamines, Random Urine
Collect random urine. Add 1 – 2 drops 6N HCl to a 10 mL urine within 4 hours of collection. Mix well, ensure pH 1-3, and send urine refrigerated in a plastic screw-capped urine cup.
High Performance Liquid Chromatography
With Preservative: 72 hours room temp, 7 days refrigerated, 1 month frozen