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ICD-10-CM 2027 diagnosis code

T85.635ALeakage of other nervous system device, implant or graft, initial encounter

✓ Billable / specificRequires 7th characterCC — complication/comorbidity

T85.635A is a valid, billable ICD-10-CM code for leakage of other nervous system device, implant or graft, initial encounter. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Leakage of other nervous sys device, implant or graft, init

Code last changed in FY2017 (effective October 1, 2016). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About T85.635A

T85.635A is the ICD-10-CM diagnosis code for leakage of other nervous system device, implant or graft, initial encounter. It belongs to category T85 (complications of other internal prosthetic devices, implants and grafts), block T80-T88 (complications of surgical and medical care, not elsewhere classified) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

The 7th character "A" means initial encounter: use it while the patient is receiving active treatment for the condition.

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 091 (Other Disorders of Nervous System with MCC, relative weight 1.7046), DRG 092 (Other Disorders of Nervous System with CC, relative weight 1.0239) and DRG 093 (Other Disorders of Nervous System without CC/MCC, relative weight 0.7783), in MDC 01 (Diseases and Disorders of the Nervous System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It was added in FY2017, effective October 1, 2016.

Before ICD-10, this condition was coded in ICD-9-CM as 996.59 (mechanical complication due to other implant and internal device, not elsewhere classified).

7th character

Ainitial encounter

CC/MCC status for this injury by encounter: CC for A; Neither CC nor MCC for D, S.

Other encounter types for T85.635:

Notes that apply from higher levels

Instructions written at a parent level also apply to T85.635A.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 996.59Mechanical complication due to other implant and internal device, not elsewhere classifiedapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2017 (effective 10/1/2016): Added
  • No changes since FY2017.

Common questions about T85.635A

Is T85.635A billable?

Yes. T85.635A is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

What does the "A" at the end of T85.635A mean?

It is the 7th character for initial encounter. Per the official guidelines, use it while the patient is receiving active treatment for the condition.

Can T85.635A be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict T85.635A as a principal diagnosis.

Is T85.635A a CC or MCC?

T85.635A is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does T85.635A group to?

T85.635A is used in the MS-DRG v44.0 logic for MS-DRG 091 (Other Disorders of Nervous System with MCC), MS-DRG 092 (Other Disorders of Nervous System with CC) and MS-DRG 093 (Other Disorders of Nervous System without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for T85.635A?

The CMS General Equivalence Mappings map T85.635A to ICD-9-CM 996.59.