Methodology:
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Stable Isotope Dilution Analysis
Special Instructions:
Tricyclic antidepressants, labetalol, and sotalol medications may elevate levels of metanephrines producing results that cannot be interpreted. If clinically feasible, it is optimal to discontinue these medications at least 1 week before collection. For advice on assessing the risk of removing patients from these medications and alternatives, you may consider consultation with a specialist in endocrinology or hypertension. Tricyclic antidepressants, labetalol, and sotalol medications may elevate levels of metanephrines producing results that cannot be interpreted. If clinically feasible, it is optimal to discontinue these medications at least 1 week before collection. For advice on assessing the risk of removing patients from these medications and alternatives, you may consider consultation with a specialist in endocrinology or hypertension. Instruct patient on 24 hour urine collection. To begin the urine collection, have the patient void. DISCARD THIS URINE SPECIMEN. This is best done with the first morning specimen. Note the time and record on the requisition. From then on collect all the urine that is voided and place in container. If more than one container is needed, please mark the first as #1 of 2 and retain on the floor until the collection is complete. The final void should be made 24 hours after the first void described earlier. The specimen should be included with the collection. REFRIGERATE 24 hour urines during collection. Mark each container with patient information, including date and time collection started and finished. Deliver specimens promptly to lab.
Lab - Aliquot 10 ml (minimum 2.0 mL) from 24 hour urine and add 15 mL 50% Acetic Acid at end of collection and record total volume.
