2026 ICD-10-CM Diagnosis Code T75.830AGulf war illness, initial encounter
T75.830A is a billable ICD-10-CM diagnosis code for gulf war illness, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 922 through 923.
Code Identity
Code Classification
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Other and unspecified effects of other external causes (T75). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Code History & ChangesHistory
New Code T75.830A was added to the ICD-10-CM code set for FY 2026, effective October 1, 2025.
Replacement T75.830A replaces the following previously assigned code(s):
- T75.89XA - Other specified effects of external causes, init encntr
Questions About T75.830AOverview
Is T75.830A (Gulf war illness) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report gulf war illness, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T75.830A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for gulf war illness, such as an emergency visit or first evaluation.
What MS-DRG does T75.830A group to?
When gulf war illness, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
