0.5 mL serum. Allow SST to clot in an upright position for
at least 30 minutes, then centrifuge sample within 1 hour
of collection. Transfer serum to a plastic transport tube.
Freeze. Critical Frozen (CFZ).
Medications that may affect results include: MAO inhibitors,
methyldopa, morphine, reserpine, and lithium. Patient
should abstain from medications for 72 hours prior to
collection upon the advice of their physician. In general,
foods that contain serotonin do not interfere significantly.
Slight increases may be seen in acute intestinal
obstruction, acute mi, cystic fibrosis, dumping syndromes
and nontropical sprue. Metastisizing carcinoid tumors often
show serotonin concentrations greater than 400 ng/mL.
When multiple tests are ordered, submit separate sample for
this test.