ICD-10-CM
ICD-10 code for Serotonin syndrome: G90.81
The closest CDC title for "Serotonin syndrome" is G90.81, Serotonin syndrome. G90.81 is a billable code.
Source: CDC ICD-10-CM FY2027 order file dated June 16, 2026. Publisher page
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Codes under G90, then other CDC titles that name serotonin syndrome
A header groups codes and is not billed. A billable code is one you can report.
- G90Disorders of autonomic nervous systemHeader
- G90.0Idiopathic peripheral autonomic neuropathyHeader
- G90.01Carotid sinus syncopeBillable
- G90.09Other idiopathic peripheral autonomic neuropathyBillable
- G90.1Familial dysautonomia [Riley-Day]Billable
- G90.2Horner's syndromeBillable
- G90.3Multi-system degeneration of the autonomic nervous systemBillable
- G90.4Autonomic dysreflexiaBillable
- G90.5Complex regional pain syndrome I (CRPS I)Header
- G90.50Complex regional pain syndrome I, unspecifiedBillable
- G90.51Complex regional pain syndrome I of upper limbHeader
- G90.511Complex regional pain syndrome I of right upper limbBillable
- G90.512Complex regional pain syndrome I of left upper limbBillable
- G90.513Complex regional pain syndrome I of upper limb, bilateralBillable
- G90.519Complex regional pain syndrome I of unspecified upper limbBillable
- G90.52Complex regional pain syndrome I of lower limbHeader
- G90.521Complex regional pain syndrome I of right lower limbBillable
- G90.522Complex regional pain syndrome I of left lower limbBillable
- G90.523Complex regional pain syndrome I of lower limb, bilateralBillable
- G90.529Complex regional pain syndrome I of unspecified lower limbBillable
- G90.59Complex regional pain syndrome I of other specified siteBillable
- G90.8Other disorders of autonomic nervous systemHeader
- G90.81Serotonin syndromeBillable
- G90.89Other disorders of autonomic nervous systemBillable
- G90.9Disorder of the autonomic nervous system, unspecifiedBillable
- G90.APostural orthostatic tachycardia syndrome [POTS]Billable
- G90.BLMNB1-related autosomal dominant leukodystrophyBillable
Code first
The CDC tabular list says to report the code named here before this one.
Code first poisoning due to drug or toxin, such as:
Use additional code
The CDC tabular list says to add the code named here after this one when it applies.
Use additional code for adverse effect, if applicable, to identify drug, such as:
- T36.8X5Linezolid
- T43.1X5Monoamine oxidase inhibitors
- T43.215Selective serotonin and norepinephrine reuptake inhibitors [SSNRI]
- T43.225Selective serotonin reuptake inhibitors [SSRI]
- code, if applicable, to identify:
- D65Disseminated intravascular coagulation
- I16.-Hypertensive crisis
- E87.2-Metabolic acidosis
- R57.-Shock, not elsewhere classified
- G92.-Toxic encephalopathy
- I47.2-Ventricular tachycardia
Excludes1
Excludes1 means these codes are not reported together.
From G90. A note on a category applies to every code under it.
Related conditions
Related pages
- G90.81 code detailsNotes, nearby codes, CMS-HCC group
- Category G90Every code under it
- Chapter 6Diseases of the nervous system
- ICD-10 codes by conditionA to Z
- Check a list of ICD-10 codes
- Denial code CO-11Diagnosis does not support the procedure
- Denial code CO-146Diagnosis invalid for the date of service
- HCPCS Level II code lookup
Questions
What is the ICD-10 code for Serotonin syndrome?
The closest CDC title for "Serotonin syndrome" is G90.81, Serotonin syndrome. G90.81 is a billable code.
Is G90.81 billable?
Yes. G90.81 is a billable code in the FY2027 ICD-10-CM file. Use a more specific code when the record documents one.
What documentation notes apply to G90.81?
The CDC tabular list gives 1 Excludes1 note (not coded together), 12 "use additional code" notes for G90.81 and the categories above it. They are listed on this page.
What chapter is G90.81 in?
Chapter 6. Diseases of the nervous system.
When do ICD-10-CM codes change?
Every October 1, with the new fiscal year file. Some years add April 1 updates. This page uses the FY2027 file, effective October 1, 2026.