Serotonin, Whole Blood

Message

Sendout, Mayo test code: SERWB

Test Code

LAB5210943

Alias/See Also

5-HT (5-Hydroxytryptamine)
5-hydroxytryptamine (5-HT)

CPT Codes
84260

Preferred Specimen

2.5 mL whole blood in a lavendar EDTA tube.

Patient Preparation
1. Patients should not eat avocados, bananas, butternuts, cantaloupe, dates, eggplant, grapefruit, hickory nuts, honeydew melon, kiwifruit, melon, nuts, pecans, pineapple, plantains, plums, tomatoes, or walnuts, which are high in serotonin for 48 hours before and during collection.
2. Patient should discontinue medications that may elevate urine serotonin concentration including lithium, monoamine oxidase-inhibitors, methyldopa, morphine, and reserpine. Patient should also discontinue use of selective serotonin reuptake inhibitors (SSRI; eg, PROZAC) that can lead to depletion of platelet serotonin levels and result in false-negative urine serotonin tests.

Minimum Volume

1.5 mL

Instructions

1. Immediately after collection, transfer approximately 2.5 mL of whole blood to the serotonin tube and mix well (any volume of whole blood from 1.5-3 mL is acceptable).
2. Immediately freeze specimen (necessary to lyse the red blood cells).

Transport Container

Serotonin Tube (T259)

Transport Temperature

Frozen

Specimen Stability

Frozen: 90 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Gross lipemia: OK
Gross icterus: OK

Methodology
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

FDA Status
Approved

Setup Schedule

Monday, Wednesday, Friday

Report Available

5 to 8 days

Limitations

Since most circulating serotonin (5-hydroxytryptamine) is contained in platelets, the preferred specimens for measurement either include all or most of the platelets (ie, whole blood and platelet-rich plasma) or consist of serum from completely clotted specimens, a process that releases nearly all serotonin from platelets. "Ordinary" or platelet-poor plasma specimens are not suitable.

Medications that may elevate serotonin concentrations include lithium, monoamine oxidase inhibitors, methyldopa, morphine, and reserpine. The observed levels are usually less than400 ng/mL. Selective serotonin reuptake inhibitors (SSRI; eg, fluoxetine) can lead to depletion of platelet serotonin levels and result in false-negative serum and blood serotonin tests. The effects of drugs are more marked on urinary serotonin and 5-hydroxyindoleacetic acid (5-HIAA) levels than on serum and blood serotonin levels.

Serotonin- or tryptophan-rich foods (eg, avocados, bananas, plums, walnuts, pineapple, eggplant, plantain, tomatoes, hickory nuts, kiwi, dates, grapefruit, cantaloupe, and honeydew melon) do not contribute significantly to serum or blood serotonin measurements, but can elevate platelet-poor plasma serotonin, urinary serotonin, and urinary 5-HIAA levels markedly (up to 10-fold).

Clinical Significance

In conjunction with, or as an alternative to, first-order tests in the differential diagnosis of isolated symptoms suggestive of carcinoid syndrome, in particular flushing (5-hydroxyindoleacetic acid or serum chromogranin A measurements are first-line tests)

Second-order test in the follow-up of patients with known or treated carcinoid tumors using whole blood specimens

Performing Laboratory
Mayo Clinic Laboratories, Rochester, Minnesota

Additional Information
Serotonin, Blood

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.