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I15 ICD-10-CM Code: Secondary hypertension

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Coding at a Glance

Tabular directives
3 Excludes1 · 3 Excludes2 · 6 use-additional codes · 1 code-also instruction

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for I15 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on I15 itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Code Also

Additional codes that may be required to fully describe the encounter.

  • underlying condition

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Source: inherited from I10-I1A

Coder workflow for I15

MedCoder structured workflow — derived from this code’s own official record

Before you code I15

  1. I15 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewI15.0, I15.1, I15.2, I15.8, I15.9

    See the relationships section · Guide: How to choose an ICD-10-CM code →

  2. Check the record for heart involvement, chronic kidney disease, a documented cause, crisis, resistance, or pregnancy: each moves the case to a different category in I10–I16 and I1A, and the classification presumes the heart and kidney links unless the provider states they are unrelated. The hypertension guideline and the “with” convention (Guidelines I.C.9.a, I.A.15).

    Guide: The "with" convention →

  3. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with I15. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support one of the more specific codes beneath I15?
    Yes → Select that code and continue the checks below on its own page.
    No → I15 cannot be reported as written; query for the specificity its subcategory needs.

    ReviewI15.0, I15.1, I15.2, I15.8, I15.9

  2. Does the documentation support a condition named in I15’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewI97.3, P29.2, I27.0

Consider I15. Then work the Use Additional Code note and review the Code Also note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.
Heart involvement, chronic kidney disease and its stage, cause, crisis, pregnancy
Each moves the case to a different hypertension category (Guidelines I.C.9.a).

Official instructions as workflow

  • Excludes1 — check before selecting I15(3 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with I15: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareI97.3, P29.2, I27.0

    See the official tabular notes · Guidelines I.A.12.a

  • Excludes2 — not part of I15(3 notes)

    Coding workflow: The conditions named in this note are not included in I15. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareH35.0

    See the official tabular notes · Guidelines I.A.12.b

  • Use Additional Code — after identifying I15(6 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with I15 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewZ77.22, Z87.891, Z57.31, F17, Z72.0

    See the official tabular notes · Guidelines I.A.13

  • Code Also — related condition(1 note)

    Coding workflow: Review the related condition when both are documented and the instruction applies. A Code Also note does not fix sequencing; the order follows the circumstances of the encounter.

    See the official tabular notes · Guidelines I.A.17

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Both the condition I15 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewI97.3, P29.2, I27.0

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with I15?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewZ77.22, Z87.891, Z57.31, F17, Z72.0

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Secondary hypertension is a non-billable ICD-10-CM category code (I15). A more specific billable subcode must be selected for claims submission.

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Official Coding Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 9: Diseases of the Circulatory System (I00 -I99)

The same heart conditions (I50.-, I51.4-I51.7, I51.89, I51.9) with hypertension are coded separately if the provider has documented they are unrelated to the hypertension. The applicable hypertension code I10, Essential (primary) hypertension, or a code from category I15, Secondary hypertension, should be assigned. Sequence according to the circumstances of the admission/encounter.

Chapter 9: Diseases of the Circulatory System (I00 -I99)

5) Hypertensive Retinopathy Subcategory H35.0, Background retinopathy and retinal vascular changes, should be used along with a code from categories I10 – I15, in the Hypertensive diseases section, to include the systemic hypertension. The sequencing is based on the reason for the encounter.

Chapter 9: Diseases of the Circulatory System (I00 -I99)

6) Hypertension, Secondary Secondary hypertension is due to an underlying condition. Two codes are required: one to identify the underlying etiology and one from category I15 to identify the hypertension. Sequencing of codes is determined by the reason for admission/encounter.

Chapter 9: Diseases of the Circulatory System (I00 -I99)

8) Hypertension, Controlled This diagnostic statement usually refers to an existing state of hypertension under control by therapy. Assign the appropriate code from categories I10-I15, Hypertensive diseases.

Chapter 9: Diseases of the Circulatory System (I00 -I99)

9) Hypertension, Uncontrolled Uncontrolled hypertension may refer to untreated hypertension or hypertension not responding to current therapeutic regimen. In either case, assign the appropriate code from categories I10-I15, Hypertensive diseases.

Chapter 9: Diseases of the Circulatory System (I00 -I99)

10) Hypertensive Crisis Assign a code from category I16, Hypertensive crisis, for documented hypertensive urgency, hypertensive emergency or unspecified hypertensive crisis. Code also any identified hypertensive disease (I10- I15). The sequencing is based on the reason for the encounter.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. 6 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  2. 1 Code Also note — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
  3. 3 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  4. 3 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name I15 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: I12 — Hypertensive chronic kidney disease.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 1 Code First instruction: I1A.0 — Resistant hypertension.

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Referenced by 1 Code Also instruction: I16 — Hypertensive crisis.

These codes suggest coding this condition alongside when both are present.

Contextual Map

Every relationship of I15 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run I15 with these 19 related codes in Claim Check

Hierarchy

Excludes1

Excludes2 (16)

Use Additional Code

Referenced by Excludes1 notes

Referenced by Code First instructions

Referenced by Code Also instructions

  • I16 — Hypertensive crisis[Code Also]: “any identified hypertensive disease (I10-I15, I1A)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Nearest codes

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Can I15 be billed directly?

No. I15 (Secondary hypertension) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "I15 — Secondary hypertension." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/i15-secondary-hypertension

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Secondary hypertension

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to I15 in its code family, with their registry titles.