1-5 days after setup at PeaceHealth Laboratories’ reference lab
Specimen Collection Details
One 4 mL lavender top tube (EDTA). Place on ice. Patient should abstain from medications for 72 hours prior to collection.
Transfer 3 mL EDTA whole blood into a whole blood serotonin collection tube containing ascorbic acid, available from PeaceHealth Laboratories Client Services. Mix well and freeze within 2 hours of collection. Critical frozen. If other tests are ordered, send separate specimen for this test.
30 days frozen. Unstable ambient or refrigerated.
3 mL whole blood.
1 mL whole blood.
Frozen on dry ice.
Medications that may affect serotonin concentrations include lithium, MAO inhibitors, methyldopa, morphine, and reserpine. In general, foods that contain serotonin do not interfere significatnly. Slight increases may be seen in acute intestinal obstruction, acute MI, cystic fibrosis, dumping syndromes, and nontropical sprue. Metastasizing abdominal carcinoid tumors often show serotonin concentrations greater than 400 ng/mL.