2026 ICD-10-CM Diagnosis Code Z89.521Acquired absence of right knee

ICD-10-CM Codes›Z00–Z99›Z77-Z99›Z89

ICD-10-CM Z89.521
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Z89.521 is a billable ICD-10-CM diagnosis code for acquired absence of right knee. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acquired absence of limb or organ.

Code Identity

ICD-10-CM Code
Z89.521
Billable Status
Yes — Valid for Submission
Code Describes
Acquired absence of right knee
Short Description
Acquired absence of right knee
Same as the full description in the CMS dataset.
Parent Code
Z89.52
Acquired absence of knee

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ77-Z99Persons with potential health hazards related to family and personal history and certain conditions influencing health status
CategoryZ89Acquired absence of limb
This CodeZ89.521Acquired absence of right knee

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z89.521.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Present on Admission (POA)Billing

Z89.521 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Clinical ClassificationClinical

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

CCSR FAC022
Acquired absence of limb or organ
Default principal diagnosis: inpatient No · outpatient Yes

Convert Z89.521 to ICD-9-CMHistory

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

ICD-9-CM
V88.22 Acq absence knee joint
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 Z89.521Overview

Is Z89.521 (Acquired absence of knee) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report acquired absence of right knee on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can Z89.521 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because acquired absence of right knee describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z89.521 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for acquired absence of right knee on inpatient claims.

What is the ICD-9 equivalent of Z89.521?

Under the General Equivalence Mappings, acquired absence of right knee converts to ICD-9-CM V88.22 (acq absence knee joint). The mapping is approximate, so confirm the match fits the documentation.