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HelpTest Code LAB121 Serotonin, Serum
Reporting Name
Serotonin, SUseful For
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
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumAdditional Testing Requirements
First-line testing for the diagnosis of carcinoid tumors with symptoms suggestive of carcinoid syndrome consists of urinary 5-HIAA (HIAA / 5-Hydroxyindoleacetic Acid, 24 Hour, Urine), and serum chromogranin A (CGAK / Chromogranin A, Serum). Serotonin in whole blood (SERWB / Serotonin, Blood), serum (SER / Serotonin, Serum), and urine (SERU / Serotonin, 24 Hour, Urine) are useful in conjunction with these first-line tests.
Specimen Required
Patient Preparation: Patient should not take medications that may elevate serotonin levels, including lithium, monoamine oxidase inhibitors, methyldopa, morphine, and reserpine, or selective serotonin reuptake inhibitors (SSRI, eg, PROZAC) which can lead to depletion of platelet serotonin levels and result in false-negative serotonin results for a minimum of 72 hours before specimen collection. Some drugs with longer half-lives (i.e. fluoxetine) can require months after discontinuation for serotonin levels to return to baseline.
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 2.5 mL
Collection Instructions: Centrifuge as soon as blood has clotted and aliquot serum into a plastic vial.
Specimen Minimum Volume
1.1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 21 days |
| Frozen | 90 days | |
| Ambient | 4 days |
Reference Values
≤230 ng/mL
Day(s) Performed
Monday, Wednesday, Friday
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84260
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| SER | Serotonin, S | 27057-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 84395 | Serotonin, S | 27057-9 |
Cautions
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 than 400 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 blood and serum 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).(1)
Report Available
5 to 8 daysReject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
NY State Approved
YesMethod Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)