I12.9: Hypertensive chronic kidney disease with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease

The ICD-10-CM code for hypertension occurring with chronic kidney disease at stage 1 through stage 4, or at an unspecified stage, when no hypertensive heart disease is documented.

Billable

FY2027

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At a glance

Code Family

I12: Hypertensive chronic kidney disease.

Condition

Hypertensive CKD

Family Specificity

Two billable child codes split on the stage of the kidney disease. I12.9 covers stages 1 through 4 and unspecified stage. I12.0 covers stage 5 and end stage renal disease.

DRG Grouping

MS-DRG 682, 683 or 684 within MDC 11 under the FY2027 MS-DRG v44 grouper, depending on complications and comorbidities.

HCC Mapping (v28)

None. I12.9 does not map to a CMS-HCC v28 category on its own. At stage 3 and stage 4, the companion N18 stage code carries the v28 mapping.

Billable

Yes, valid for HIPAA-covered transactions.

Which I12 code do I assign?

The I12 family splits on the stage of the documented chronic kidney disease. The choice between category I12 and category I13 turns instead on whether heart disease is documented alongside the hypertension and the kidney disease.

When documentation says…

Code

Hypertension with CKD stage 3a

I12.9

Hypertension with chronic kidney disease at stage 1 through stage 4, or at an unspecified stage. The note must document both conditions as current diagnoses. A companion code from N18.1 through N18.4, or N18.9, must be added to identify the stage.

Hypertension with ESRD on dialysis

I12.0

Hypertension with chronic kidney disease at stage 5, or with end stage renal disease. The companion stage code is N18.5 or N18.6. Neither of those two codes may be paired with I12.9.

Hypertension, CKD stage 4 and chronic diastolic heart failure

I13.0

Hypertensive heart and chronic kidney disease with heart failure, at CKD stage 1 through stage 4 or unspecified stage. Under Guideline Section I.C.9.a.3, a code from category I13 is used instead of a code from category I12. I12.9 is not reported at the same encounter.

Hypertensive heart disease and CKD stage 2, no heart failure

I13.10

Hypertensive heart and chronic kidney disease without heart failure, at CKD stage 1 through stage 4 or unspecified stage. The note must document a heart condition classified to I51.4-I51.7, I51.89 or I51.9, which the classification presumes is due to the hypertension.

Hypertension with no kidney disease documented

I10

Essential hypertension on its own. Assign this when the record documents no chronic kidney disease. I10 is not reported additionally at an encounter where I12.9 is assigned.

Hypertension documented as caused by the renal disorder

I15.1

Hypertension secondary to other renal disorders. The direction of causality is reversed here. Category I12 does not apply. The appropriate N18 stage code is still reported.

Tabular notes

USE ADDITIONAL

Use additional code to identify the stage of chronic kidney disease: N18.1 through N18.4, or N18.9. This instruction is mandatory rather than optional. I12.9 is incomplete without a companion N18 stage code. N18.5 and N18.6 are the companions for I12.0 and are not valid with I12.9.

EXCLUDES1

Category I12 carries an Excludes1 note for hypertension due to kidney disease (I15.0, I15.1), renovascular hypertension (I15.0) and secondary hypertension (I15.-), which are classified to category I15. An Excludes1 note means the two codes are not reported together for the same condition. No Excludes1 note links categories I12 and I13. The Includes note at I13 brings the conditions of categories I11 and I12 together in one combination code. Under Guideline Section I.C.9.a.3, where hypertension, chronic kidney disease and heart disease are all documented, a code from category I13 is used instead of a code from category I12.

FY2027: EFFECTIVE 1 OCTOBER 2026

The FY2027 codes addenda make no addition, deletion or revision in category I12. The FY2027 tabular addenda make no change to the I12 or I12.9 instructional notes. I12.9 is unchanged in the FY2027 update.

Operational & financial impact

Why specificity matters beyond the chart: risk adjustment, DRG assignment and denial exposure all follow from which code is selected.

CMS-HCC v28 (PY2024+)

I12.9 does not map to a CMS-HCC v28 category on its own. The risk adjustment weight is carried by the mandatory companion N18 stage code.

N18.30 and N18.31 map to HCC 329: chronic kidney disease, moderate, stage 3 except 3B.

N18.32 maps to HCC 328: chronic kidney disease, moderate, stage 3B.

N18.4 maps to HCC 327: chronic kidney disease, stage 4.

N18.1, N18.2 and N18.9 carry no HCC mapping in CMS-HCC v28.

MS-DRG v44 (FY2027)

MS-DRG 682: renal failure with MCC.

MS-DRG 683: renal failure with CC.

MS-DRG 684: renal failure without CC/MCC.

I12.9 as a principal inpatient diagnosis groups under MDC 11, diseases and disorders of the kidney and urinary tract, in the FY2027 MS-DRG v44 grouper. Tier assignment is determined by the presence of a major complication or comorbidity, or of a complication or comorbidity, across the full diagnostic code set. The companion N18 stage code may itself qualify: N18.4 is a CC on the FY2027 list.

WHERE SPECIFICITY IS LOST

N18.9, Chronic kidney disease, unspecified, carries no HCC mapping. A record that documents chronic kidney disease without a stage returns no risk adjustment weight. A staged record at stage 3 or stage 4 maps to HCC 327, HCC 328 or HCC 329. Query the provider for the stage whenever chronic kidney disease is documented without one.

Medicare and commercial payers

For Medicare, I12.9 is reported with its N18 stage companion. At stage 3 and stage 4, the N18 code carries the v28 HCC mapping used in Medicare Advantage risk adjustment.

Documentation checklist to support I12.9

Chart elements that support code selection and reduce specificity-driven denials.

Hypertension documented as a current diagnosis, whether recorded as essential hypertension, HTN or high blood pressure in the problem list or the assessment.

Chronic kidney disease documented as a current diagnosis, whether recorded as CKD, chronic renal insufficiency or chronic renal failure.

The chronic kidney disease stage, recorded as stage 1, stage 2, stage 3a, stage 3b or stage 4. The documented stage determines which N18 companion code is selected.

An explicit statement of unspecified stage where no stage is known, which supports N18.9. A staged record supports more accurate risk adjustment.

The absence of documented heart disease. Where hypertensive heart disease or heart failure is also documented, category I13 replaces category I12.

The absence of any statement that the hypertension and the chronic kidney disease are unrelated. Query the provider where the record is uncertain.

The direction of causality where the provider addresses it. Hypertension documented as caused by a renal disorder directs the encounter to I15.1 rather than to category I12.

Evidence that both conditions were addressed or monitored at the encounter, recorded on a dated encounter note rather than only on a problem list.

FAQ

Is I12.9 a billable code?

Yes. I12.9 is a valid billable code for HIPAA-covered transactions. It is never reported alone. A companion N18 code identifying the chronic kidney disease stage must accompany it.

When do I use I12.9 instead of I12.0?

Use I12.9 when the documented chronic kidney disease is stage 1 through stage 4, or when the stage is unspecified. Use I12.0 when the documentation shows stage 5 chronic kidney disease or end stage renal disease. The companion codes N18.5 and N18.6 belong with I12.0 and are not valid with I12.9.

What if heart disease is documented as well as the hypertension and the kidney disease?

Category I13, hypertensive heart and chronic kidney disease, is then the correct category. I13 carries an Excludes1 relationship with I12. The two are never reported together for the same encounter. Use I13.0 where heart failure is documented at CKD stage 1 through stage 4 or unspecified stage. Use I13.10 where the heart disease is documented without heart failure at those same stages.

Does the provider have to state that the hypertension caused the chronic kidney disease?

No. ICD-10-CM presumes a cause and effect relationship and classifies chronic kidney disease with hypertension as hypertensive chronic kidney disease. Official Guidelines Section I.C.9.a directs assignment of a code from category I12 whenever both conditions are present. The provider would have to document explicitly that the two conditions are unrelated to override that convention.

Does I12.9 map to an HCC under CMS-HCC v28?

No. I12.9 carries no CMS-HCC v28 mapping of its own. The risk adjustment weight sits with the companion N18 stage code. N18.30 and N18.31 map to HCC 329, N18.32 maps to HCC 328, and N18.4 maps to HCC 327. N18.1, N18.2 and N18.9 carry no mapping.

How are I12.9 and the N18 stage code sequenced?

Sequence I12.9 first and the N18 stage code second as an additional diagnosis, per Official Guidelines Section I.C.9.a.2. The N18 code identifies the stage of chronic kidney disease. Sequencing the N18 code first is a coding error.

How does I12.9 behave on the inpatient side compared with the outpatient side?

As a principal inpatient diagnosis, I12.9 groups to MS-DRG 682, 683 or 684 under MDC 11. Where the admission is for a different condition, I12.9 appears as a secondary code. In the outpatient setting, the N18 companion must accompany I12.9 at every encounter where both conditions are addressed or monitored.

What changed for I12.9 in FY2027?

I12.9 is unchanged in the FY2027 update. The FY2027 update, effective 1 October 2026, makes no addition, deletion or revision in category I12 and no change to its instructional notes.

Related codes

Codes in the same family as I12.9. Only codes with a published page render as links.

Sibling codes in the I12 family

I12.0: Hypertensive chronic kidney disease with stage 5 chronic kidney disease or end stage renal disease.

Additional codes to consider

Codes outside the I12 family considered alongside I12.9.

Companion: code alongside when documented

N18.1: Chronic kidney disease, stage 1.
N18.2: Chronic kidney disease, stage 2 (mild).
N18.30: Chronic kidney disease, stage 3 unspecified.
N18.31: Chronic kidney disease, stage 3a.
N18.32: Chronic kidney disease, stage 3b.
N18.4: Chronic kidney disease, stage 4 (severe).
N18.9: Chronic kidney disease, unspecified, where the record documents no stage.

Consider instead

I12.0: Hypertensive chronic kidney disease with stage 5 chronic kidney disease or end stage renal disease, paired with N18.5 or N18.6.
I13.0: Hypertensive heart and chronic kidney disease with heart failure and stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease.
I13.10: Hypertensive heart and chronic kidney disease without heart failure, with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease.
I10: Essential (primary) hypertension, where no chronic kidney disease is documented.
I15.1: Hypertension secondary to other renal disorders, where the provider documents the renal disorder as the cause of the hypertension.

Sources

All claims on this page derive from government and professional-standards sources.

National Center for Health Statistics. (2026). International classification of diseases, tenth revision, clinical modification (ICD-10-CM) FY2027 files. https://www.cdc.gov/nchs/icd/icd-10-cm/files.html
Centers for Medicare & Medicaid Services and National Center for Health Statistics. (2026). ICD-10-CM official guidelines for coding and reporting FY2027. https://ftp.cdc.gov/pub/Health_Statistics/NCHS/Publications/ICD10CM/2027/ICD-10-CM-October-1-2026-FY27-Guidelines.pdf
Centers for Medicare & Medicaid Services. (2025). 2026 model software/ICD-10 mappings. https://www.cms.gov/medicare/payment/medicare-advantage-rates-statistics/risk-adjustment/2026-model-software-icd-10-mappings
Centers for Medicare & Medicaid Services. (2026). MS-DRG classifications and software, version 44. https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps/ms-drg-classifications-and-software