I16.1 ICD-10-CM Code: Hypertensive emergency

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for I16.1 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 I16.1 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for I16.1

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

Before you code I16.1

1. 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 →

2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with I16.1. 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 a condition named in I16.1’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.

   ReviewP29.2, I27.0

Consider I16.1. 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 I16.1(2 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with I16.1: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareP29.2, I27.0

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

• Excludes2 — not part of I16.1(1 note)

  Coding workflow: The conditions named in this note are not included in I16.1. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

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

• Use Additional Code — after identifying I16.1(6 notes)

  Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with I16.1 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(11 notes)

  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.

  ReviewN17, I21, J81.0, I50, I71.0, I60

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

Coding decision scenarios

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

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.

Indexed Clinical Terms (1)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Hypertension, hypertensive (accelerated) (benign) (essential) (idiopathic) (malignant) (systemic), emergency

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.

Don’t confuse I16.1 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of I16.1 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• P29.2— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of neonatal hypertension moves the case to P29.2; the two are not reported together unless documented as unrelated.

  Full comparison: I16.1 vs P29.2 →

• I27.0— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of primary pulmonary hypertension moves the case to I27.0; the two are not reported together unless documented as unrelated.

  Full comparison: I16.1 vs I27.0 →

• I16.9— Specificity relationship (Review)

  Overlapping diagnoses in the same category.

  Overlapping codes in the same category — the documentation decides which is the more specific fit.

  What moves you there: A record that documents no more than “Hypertensive crisis, unspecified” takes I16.9; specificity in the record moves it back here.

  Full comparison: I16.1 vs I16.9 →

• O10— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of hypertensive disease complicating pregnancy, childbirth and the puerperium adds O10; it is not part of this code and both may be reported when both are documented.

  Full comparison: I16.1 vs O10 →

• O11— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of hypertensive disease complicating pregnancy, childbirth and the puerperium adds O11; it is not part of this code and both may be reported when both are documented.

  Full comparison: I16.1 vs O11 →

• O13— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of hypertensive disease complicating pregnancy, childbirth and the puerperium adds O13; it is not part of this code and both may be reported when both are documented.

  Full comparison: I16.1 vs O13 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

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. 11 Code Also notes — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
3. 2 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
4. 1 Excludes2 entry — 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

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

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 I16.1 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 Use Additional Code instruction: G90.81 — Serotonin syndrome (via I16.-).

These codes instruct coders to additionally report this code when it applies.

Referenced by 1 Code Also instruction: D59.39 — Other hemolytic-uremic syndrome.

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

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 1 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 2 MS-DRGs: DRG 304 (MDC 05), DRG 305 (MDC 05).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):CIR008 — Hypertension with complications and secondary hypertension (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Hypertension with complications and secondary hypertension).

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, I13.11 — Hypertensive heart and chronic kidney disease without heart failure, with stage 5 chronic kidney disease, or end stage renal disease, I13.2 — Hypertensive heart and chronic kidney disease with heart failure and with stage 5 chronic kidney disease, or end stage renal disease, I15.0 — Renovascular hypertension, I15.1 — Hypertension secondary to other renal disorders, I15.2 — Hypertension secondary to endocrine disorders, I15.8 — Other secondary hypertension, I15.9 — Secondary hypertension, unspecified, I16.0 — Hypertensive urgency, I16.9 — Hypertensive crisis, unspecified, I1A.0 — Resistant hypertension, I67.4 — Hypertensive encephalopathy, I97.3 — Postprocedural hypertension, O10.111 — Pre-existing hypertensive heart disease complicating pregnancy, first trimester, O10.112 — Pre-existing hypertensive heart disease complicating pregnancy, second trimester, O10.113 — Pre-existing hypertensive heart disease complicating pregnancy, third trimester, O10.119 — Pre-existing hypertensive heart disease complicating pregnancy, unspecified trimester, O10.12 — Pre-existing hypertensive heart disease complicating childbirth, O10.13 — Pre-existing hypertensive heart disease complicating the puerperium, +37 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Hypertension, hypertensive”; these codes share that main term but sit in a different category of the Tabular List.

I12.9 — Hypertensive chronic kidney disease with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease (kidney), 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 (cardiorenal, with heart failure), 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 (cardiorenal), I13.11 — Hypertensive heart and chronic kidney disease without heart failure, with stage 5 chronic kidney disease, or end stage renal disease (cardiorenal, without heart failure, with stage 5 or end stage renal disease), I13.2 — Hypertensive heart and chronic kidney disease with heart failure and with stage 5 chronic kidney disease, or end stage renal disease (cardiorenal, with heart failure, with stage 5 or end stage renal disease), I15.0 — Renovascular hypertension (renovascular), I15.1 — Hypertension secondary to other renal disorders (due to, renal disorders NEC), I15.2 — Hypertension secondary to endocrine disorders (due to, pheochromocytoma), I15.8 — Other secondary hypertension (secondary NEC, specified NEC), I15.9 — Secondary hypertension, unspecified (secondary NEC), I1A.0 — Resistant hypertension (resistant), I26.09 — Other pulmonary embolism with acute cor pulmonale (pulmonary, with, cor pulmonale, acute), I27.0 — Primary pulmonary hypertension (lesser circulation), I27.1 — Kyphoscoliotic heart disease (pulmonary, due to, kyphoscoliotic heart disease), I27.20 — Pulmonary hypertension, unspecified (pulmonary), I27.21 — Secondary pulmonary arterial hypertension (pulmonary, group 1), I27.22 — Pulmonary hypertension due to left heart disease (pulmonary, group 2), I27.23 — Pulmonary hypertension due to lung diseases and hypoxia (pulmonary, group 3), I27.24 — Chronic thromboembolic pulmonary hypertension (pulmonary, group 4), I27.29 — Other secondary pulmonary hypertension (pulmonary, group 5), +52 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Lipid Panel, Partial Thromboplastin Time (PTT) Test, Prothrombin Time Test and INR (PT/INR), Thyroid Stimulating Hormone (TSH)

Contextual Map

Every relationship of I16.1 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 I16.1 with these 10 related codes in Claim Check

Hierarchy

• I00-I99 — Chapter 9: Diseases of the Circulatory System (I00-I99) (I00-I99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• I10-I1A — Hypertensive diseases[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Code Also (12)

• I21 — Acute myocardial infarction[Code Also]: “acute myocardial infarction (I21.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I50 — Heart failure[Code Also]: “acute pulmonary edema (left and/or right ventricular failure) (J81.0, I50.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I60 — Nontraumatic subarachnoid hemorrhage[Code Also]: “cerebral hemorrhage (I60.-. I61.-, I62.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I61 — Nontraumatic intracerebral hemorrhage[Code Also]: “cerebral hemorrhage (I60.-. I61.-, I62.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I62 — Other and unspecified nontraumatic intracranial hemorrhage[Code Also]: “cerebral hemorrhage (I60.-. I61.-, I62.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I63 — Cerebral infarction[Code Also]: “cerebral infarction (I63.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I67.4 — Hypertensive encephalopathy[Code Also]: “hypertensive encephalopathy (I67.4)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I71.0 — Dissection of aorta[Code Also]: “aortic dissection (I71.0-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• and 4 more

Referenced by Use Additional Code instructions

• G90.81 — Serotonin syndrome[Use Additional Code](via I16.-): “hypertensive crisis (I16.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Code Also instructions

• D59.39 — Other hemolytic-uremic syndrome[Code Also]: “hypertensive emergency (I16.1)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• CIR008 — Hypertension with complications and secondary hypertension[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 304 — HYPERTENSION WITH MCC[MS-DRG]: “HYPERTENSION WITH MCC (MDC 05)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 305 — HYPERTENSION WITHOUT MCC[MS-DRG]: “HYPERTENSION WITHOUT MCC (MDC 05)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 05 — Diseases and Disorders of the Circulatory System[MDC crossing]: “Diseases and Disorders of the Circulatory System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 17,209 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Hypertension, hypertensive (accelerated) (benign) (essential) (idiopathic) (malignant) (systemic), emergency[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• I16 — Hypertensive crisis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• I16.0 — Hypertensive urgency[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• I16.9 — Hypertensive crisis, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Change history

• FY2017 — Added to the code set[Change history]— CMS release files (code change ledger) · icd10cm-fy2017

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

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to I16.1 in its code family, with their registry titles.

• I16 — Hypertensive crisis
• I16.0 — Hypertensive urgency
• I16.9 — Hypertensive crisis, unspecified

View all codes in the I16 family