Alphabetic Index FY2027

G92.04

Immune effector cell-associated neurotoxicity syndrome, grade 4

FY2027Chapter 6: Diseases of the nervous system/G89–G99 Other disorders of the nervous system

BillableComplete code, valid to report
Care settingsIRF 60% RuleHospice: not accepted as primaryHospital CC

G92.04 (also written G9204) is a billable ICD-10-CM diagnosis code for immune effector cell-associated neurotoxicity syndrome, grade 4. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 8 codes in category G92 (Toxic encephalopathy). The Alphabetic Index lists it under 1 entry. Its coding notes include a Code first instruction, a Code also instruction and 8 Excludes2 entries.

Code first

If the underlying condition listed here is present and known, sequence it first.

Inherited from G92.0 Immune effector cell-associated neurotoxicity syndrome
  • underlying cause such as:
    • complications of immune effector cellular therapy (T80.82)

Code also

Two codes may be needed to describe the condition. This note gives no sequencing order.

Inherited from G92.0 Immune effector cell-associated neurotoxicity syndrome
  • , if applicable, associated signs and symptoms, such as:
    • cerebral edema (G93.6)
    • unspecified convulsions (R56.9)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (8 notes)
Inherited from Chapter 6 Diseases of the nervous system
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

IRF 60% Rule

On the CMS list of diagnoses used to determine presumptive compliance with the IRF 60 percent rule.

Source: CMS IRF Presumptive Compliance-3, FY 2027 IRF PPS final rule files, effective for discharges on or after October 1, 2026

Hospice: not accepted as primary

Not accepted as the principal diagnosis on a hospice claim (bill types 081x and 082x). The Integrated OCE returns an edit for this code.
Reason: Supplementary or additional code, not allowed as principal diagnosis.

Source: CMS Integrated Outpatient Code Editor (IOCE) v27.3, effective October 1, 2026, edit 113

Hospital CC

Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 52 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

Inclusion terms

Conditions classified to this code.

This code
  • ICANS, grade 4

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 1 entry