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Test Code HTR2 Serotonin Receptor Genotype (HTR2A and HTR2C)

Reporting Name

Serotonin Receptor 2A/2C Genotype

Useful For

Guiding treatment choice of a selective serotonin reuptake inhibitor (SSRI) or non-SSRI antidepressant


Guiding treatment choice in individuals who have a drug-metabolizer phenotype discordant with CYP450 genotypes


Identifying patients who may benefit from treatment with the antipsychotic drug clozapine and aripiprazole


Identifying those patients at risk of excessive weight gain when receiving antipsychotic medications

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Whole Blood EDTA

Specimen Required

Multiple whole blood EDTA genotype tests can be performed on a single specimen after a single extraction. See Multiple Whole Blood EDTA Genotype Tests in Special Instructions for a list of tests that can be ordered together.


Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood EDTA Ambient (preferred)

Reference Values

An interpretive report will be provided.

Day(s) and Time(s) Performed

Wednesday; 8 a.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81479-Unlisted molecular pathology procedure

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HTR2 Serotonin Receptor 2A/2C Genotype 46726-6


Result ID Test Result Name Result LOINC Value
83303 HTR2 Genotype 46726-6
28352 HTR2A -1438G>A 75726-0
26323 HTR2A 74C>A 75728-6
28054 HTR2A 102 T>C 75731-0
28353 HTR2A IVS2 A>G 75727-8
26324 HTR2A 1354 C>T 75729-4
19497 HTR2C -759 C>T 75732-8
26325 HTR2C 796 G>C 75730-2
26326 Reviewed By No LOINC Needed

Method Name

Polymerase Chain Reaction (PCR) with Allele-Specific Primer Extension (ASPE)


New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.