Patient Preparation: Administration of L-dopa may falsely increase homovanillic acid results; it should be discontinued 24 hours prior to and during collection of specimen.Collection Instructions:
1. Collect a 24-hour urine specimen.
2. Collection duration and urine volume are required.
3. Patient’s age is required.
4. Add 25 mL of 50% acetic acid as preservative at start of collection. If specimen is refrigerated during collection, preservative may be added up to 12 hours after collection. Use 15 mL of 50% acetic acid for children less than 5 years old. This preservative is intended to achieve a pH of between approximately 1 and 5. If necessary, adjust urine pH to 1 to 5 with 50% acetic or HCI acid.
Additional Information:
-The sensitivity of this test is greater on a 24-hour specimen than on a random specimen.