Ordering Recommendation

Use to diagnose and monitor carcinoid tumors. Preferred serotonin test since most of the blood serotonin resides in the platelets.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Abstain from medications for 72 hours prior to collection.


Lavender (EDTA) or pink (K2EDTA).

Specimen Preparation

Place on ice. Transfer 3 mL whole blood to an ARUP Serotonin Transport Tube containing ascorbic acid (ARUP supply #16568). Available online through eSupply using ARUP Connect™ or contact ARUP Client Services at (800) 522-2787. (Min: 1 mL) Mix well. Specimen must be preserved and frozen within 2 hours of collection.

Storage/Transport Temperature

CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.

Unacceptable Conditions

Non-frozen specimens. Specimens other than whole blood.


Serotonin, Serum (ARUP test code 0080397) is recommended for patients that are difficult to draw.


After transfer to Serotonin Transport Tube: Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 1 month


Quantitative High Performance Liquid Chromatography (HPLC)


Mon, Wed, Thu, Fri, Sat


1-5 days

Reference Interval

50-200 ng/mL

Interpretive Data

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)


Medications that may affect serotonin concentrations include lithium, MAO inhibitors, methyldopa, morphine, and reserpine.  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.  Metastasizing abdominal carcinoid tumors often show serotonin concentrations greater than 400 ng/mL.

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0080395 Serotonin, Whole Blood 2939-7
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • 5-HT
  • 5-Hydroxy Tryptamine
  • 5-Hydroxytryptamine
Serotonin, Whole Blood