The ICD-10-CM code for essential hypertension when blood pressure is elevated without an identified secondary cause and without documented heart disease or chronic kidney disease that would call for a combination code.
MS-DRG 304 or 305 in MDC 05 under the FY2027 MS-DRG v44 grouper, depending on whether a secondary MCC is reported.
HCC Mapping (v28)
None: I10 does not map to any CMS-HCC v28 category.
Condition
Hypertension
Family Specificity
I10 is the standalone essential hypertension code. The combination codes I11, I12 and I13 apply once chronic kidney disease or a heart condition classified to I50.-, I51.4-I51.7, I51.89 or I51.9 is documented.
Which hypertension code do I assign?
I10 is the essential hypertension code. It applies when hypertension exists without chronic kidney disease and without a heart condition classified to I50.-, I51.4-I51.7, I51.89 or I51.9. Guideline I.C.9.a presumes a causal relationship between hypertension and those conditions unless the documentation clearly states they are unrelated. A combination code from I11, I12 or I13 then replaces I10.
When documentation says…
Code
Hypertension with both heart disease and 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. Assign with a Use Additional code from N18.1-N18.4 or N18.9 for the CKD stage.
Hypertensive heart disease with heart failure
I11.0
Assign when hypertension coexists with a heart condition classified to I50.-, and add a Use Additional code from I50.- for the heart failure type.
Hypertensive heart disease without heart failure
I11.9
The combination code when hypertension and a heart condition classified to I51.4-I51.7, I51.89 or I51.9 are documented together without heart failure.
Hypertension with chronic kidney disease
I12.9
Hypertensive chronic kidney disease, stage 1 to 4 or unspecified, with a Use Additional code from N18 for the CKD stage. Do not report I10 and N18.x as separate, unrelated codes when both conditions are documented, unless the provider states the CKD is not related to the hypertension.
Resistant hypertension documented by the provider
I1A.0
Resistant hypertension. Assign as an additional code when the provider documents apparent treatment resistant, treatment resistant or true resistant hypertension. The specific type of hypertension, such as I10, is sequenced first.
Hypertension with a documented underlying cause
I15.-
Secondary hypertension, such as renovascular (I15.0), other renal (I15.1) or endocrine (I15.2). Secondary codes require a documented underlying cause.
Hypertension with no identified secondary cause and no documented heart or kidney involvement
I10
The standalone essential hypertension code, correct only when hypertension exists without chronic kidney disease and without a heart condition classified to I50.-, I51.4-I51.7, I51.89 or I51.9.
Tabular notes
EXCLUDES1
Hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16). Hypertension in pregnancy is coded from the obstetric chapter, not from I10.
EXCLUDES2
Essential (primary) hypertension involving vessels of brain (I60-I69) and essential (primary) hypertension involving vessels of eye (the H35.0- codes). Excludes2 means the excluded condition is not part of I10. Both codes may be reported together when both conditions are documented. Guideline I.C.9.a.4 sequences the I60-I69 code first for hypertensive cerebrovascular disease.
GUIDELINE I.C.9.A.1: HYPERTENSION WITH HEART DISEASE
Hypertension with a heart condition classified to I50.-, I51.4, I51.89 or I51.9 is assigned to a code from category I11. An additional code from I50 or I51 identifies the heart condition. Hypertension with I51.5 or I51.7 is assigned to I11 with no additional code. The conditions are coded separately, with I10 or I15, only when the provider documents they are unrelated.
A causal relationship is assumed between hypertension and chronic kidney disease unless the provider indicates the CKD is not related to the hypertension. Assign I12.- for hypertensive chronic kidney disease with a Use Additional code from N18 for the CKD stage, rather than reporting I10 and N18.x as separate, unrelated codes.
GUIDELINE I.C.9.A.12: RESISTANT HYPERTENSION
Assign I1A.0 as an additional code when the provider documents apparent treatment resistant hypertension, treatment resistant hypertension or true resistant hypertension. A code for the specific type of existing hypertension, such as I10, is sequenced first, if known.
FY2027 CODE CHANGES
The FY2027 ICD-10-CM codes addenda make no addition, deletion or revision in the I10-I1A block. The FY2027 tabular addenda make no change to the I10 instructional notes. I10 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+)
No HCC mapping applies to I10 in CMS-HCC v28.
I10 did not map to any HCC under CMS-HCC v24 either.
Among the combination codes, I11.0, I13.0 and I13.2 map to HCC 226: Heart Failure, Except End-Stage and Acute. I12.0, I13.11 and I13.2 map to HCC 326: Chronic Kidney Disease, Stage 5. I11.9, I12.9 and I13.10 map to no v28 HCC.
MS-DRG v44 (FY2027)
I10 as the principal inpatient diagnosis groups to MS-DRG 304, Hypertension with MCC, or MS-DRG 305, Hypertension without MCC, in MDC 05 under the FY2027 MS-DRG v44 grouper. A secondary diagnosis on the MCC list moves the case to MS-DRG 304. A CC alone leaves the case in MS-DRG 305. I10 is on neither the FY2027 CC list nor the MCC list. Documented hypertensive urgency, emergency or crisis takes a code from category I16. Guideline I.C.9.a.10 directs coding I10 also.
Medicare and commercial payers
I10 is a valid diagnosis code for Medicare claims.
Documentation checklist to support I10
Chart elements that support code selection and reduce specificity-driven denials.
FAQ
Should I always use I11.x instead of I10 when a patient has both hypertension and cardiac disease?
No. A code from category I11 applies only when the cardiac condition is classified to I50.-, I51.4-I51.7, I51.89 or I51.9. For those conditions, Guideline I.C.9.a.1 presumes a causal relationship and assigns a code from category I11, unless the provider documents that the conditions are unrelated. Other heart conditions, such as coronary artery disease (I25.10), fall outside the I11 Includes note. They are coded separately alongside I10.
Does I10 generate any risk-adjustment weight in CMS-HCC v28?
No. I10 does not map to any HCC in CMS-HCC v28. I10 did not map to any HCC under CMS-HCC v24 either. In v28, I11.0, I13.0 and I13.2 map to HCC 226: Heart Failure, Except End-Stage and Acute. I12.0, I13.11 and I13.2 map to HCC 326: Chronic Kidney Disease, Stage 5.
Related codes
Codes in the same family as I10. Only codes with a published page render as links.
Sibling codes in the I10 family
I10: Essential (primary) hypertension.
I11.0: Hypertensive heart disease with heart failure.
I11.9: Hypertensive heart disease without heart failure.
I12.9: Hypertensive chronic kidney disease with 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.
I1A.0: Resistant hypertension.
Additional codes to consider
Codes outside the I10 family considered alongside I10.
Companion: code alongside when documented
I50-: Heart failure. Required as a Use Additional code with I11.0.
N18-: Chronic kidney disease (CKD). Required as a Use Additional code with I12 to identify the stage.
Consider instead
I11-: Hypertensive heart disease. Use instead of I10 when a heart condition classified to I50.-, I51.4-I51.7, I51.89 or I51.9 is documented with hypertension.
I12-: Hypertensive chronic kidney disease. Use instead of I10 when chronic kidney disease is documented with hypertension.
I13-: Hypertensive heart and chronic kidney disease. Use instead of I10 when both are documented.
I15-: Secondary hypertension. Use instead of I10 when an underlying cause such as renovascular, other renal or endocrine disease is documented.
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
