2026 ICD-10-CM Diagnosis Code T85.591AOther mechanical complication of esophageal anti-reflux device, initial encounter

ICD-10-CM Codes›S00–T88›T80-T88›T85

ICD-10-CM T85.591A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T85.591A is a billable ICD-10-CM diagnosis code for other mechanical complication of esophageal anti-reflux device, 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 919 through 921. 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
T85.591A
Billable Status
Yes — Valid for Submission
Code Describes
Other mechanical complication of esophageal anti-reflux device, initial encounter
Short Description
Mech compl of esophageal anti-reflux device, init encntr
Parent Code
T85.591
Other mechanical complication of esophageal anti-reflux device

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 CodeT85.591AOther mechanical complication of esophageal anti-reflux device, 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 T85.591A to ICD-9-CMHistory

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

ICD-9-CM
996.59 Malfunc oth device/graft
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T85.591AOverview

Is T85.591A a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other mechanical complication of esophageal anti-reflux device, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in T85.591A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for other mechanical complication of esophageal anti-reflux device, such as an emergency visit or first evaluation.

What MS-DRG does T85.591A group to?

When other mechanical complication of esophageal anti-reflux device, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 919, 920, 921, with relative weights from 0.6884 to 1.8308 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of T85.591A?

Under the General Equivalence Mappings, other mechanical complication of esophageal anti-reflux device, initial encounter converts to ICD-9-CM 996.59 (malfunc oth device/graft). The mapping is approximate, so confirm the match fits the documentation.