2026 ICD-10-CM Diagnosis Code T85.850AStenosis due to nervous system prosthetic devices, implants and grafts, initial encounter

ICD-10-CM Codes›S00–T88›T80-T88›T85

ICD-10-CM T85.850A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T85.850A is a billable ICD-10-CM diagnosis code for stenosis due to nervous system prosthetic devices, implants and grafts, 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). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complication of other surgical or medical care, injury, initial encounter.

Code Identity

ICD-10-CM Code
T85.850A
Billable Status
Yes — Valid for Submission
Code Describes
Stenosis due to nervous system prosthetic devices, implants and grafts, initial encounter
Short Description
Stenosis due to nervous system prosth dev/grft, init
Parent Code
T85.850
Stenosis due to nervous system prosthetic devices, implants and grafts

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT80-T88Complications of surgical and medical care, not elsewhere classified
CategoryT85Complications of other internal prosthetic devices, implants and grafts
This CodeT85.850AStenosis due to nervous system prosthetic devices, implants and grafts, initial encounter

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Complications of other internal prosthetic devices, implants and grafts (T85). 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.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ037
Complication of other surgical or medical care, injury, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Convert T85.850A to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
996.75 Comp-nerv sys dev/graft
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement T85.850A replaces the following previously assigned code(s):

  • T85.85XA - Stenosis due to internal prosth dev/grft, NEC, init
FY 2018AddedAdded to the ICD-10-CM code setEffective October 1, 2017.
FY 2019–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T85.850AOverview

Is T85.850A a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report stenosis due to nervous system prosthetic devices, implants and grafts, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in T85.850A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for stenosis due to nervous system prosthetic devices, implants and grafts, such as an emergency visit or first evaluation.

What is the ICD-9 equivalent of T85.850A?

Under the General Equivalence Mappings, stenosis due to nervous system prosthetic devices, implants and grafts, initial encounter converts to ICD-9-CM 996.75 (comp-nerv sys dev/graft). The mapping is approximate, so confirm the match fits the documentation.