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ICD-10/R29.721

R29.721 ICD-10-CM Code: NIHSS score 21

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

  • MS-DRG 951 — OTHER FACTORS INFLUENCING HEALTH STATUS (MDC 23)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Official Registry Overview & Definition

NIHSS score 21 is a billable ICD-10-CM diagnosis code (R29.721).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for R29.721 in the official ICD-10-CM tabular list.

Code First

Underlying conditions that must be sequenced before this code.

  • the type of cerebral infarction (I60.-, I61.-, I62.-, I63.-)

Change history

  • FY2027 — 2026-10-01
    Code First note added
    the type of cerebral infarction (I60.-, I61.-, I62.-, I63.-)
    FY2027 changes
  • FY2027 — 2026-10-01
    Code First note removed
    the type of cerebral infarction (I63.-)
    FY2027 changes
  • FY2017 — 2016-10-01
    Added to the code set
    NIHSS score 21
    FY2017 changes

Verify Before Coding

  • Principal-diagnosis restriction. The Medicare Code Editor lists this code as unacceptable as a principal diagnosis: it describes a circumstance influencing health status rather than a current illness or injury being treated. It is valid as a secondary diagnosis.

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

Contextual Map

Every relationship of R29.721 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.

Hierarchy

  • R00-R99 — Chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99) (R00-R99) [Hierarchy]
  • R25-R29 — Symptoms and signs involving the nervous and musculoskeletal systems [Hierarchy]

Referenced by Use Additional Code instructions

  • I60 — Nontraumatic subarachnoid hemorrhage [Use Additional Code](via R29.7.-): “code, if known, to indicate National Institutes of Health Stroke Scale (NIHSS) score (R29.7-)” · check together
  • I61 — Nontraumatic intracerebral hemorrhage [Use Additional Code](via R29.7.-): “code, if known, to indicate National Institutes of Health Stroke Scale (NIHSS) score (R29.7-)” · check together
  • I62 — Other and unspecified nontraumatic intracranial hemorrhage [Use Additional Code](via R29.7.-): “code, if known, to indicate National Institutes of Health Stroke Scale (NIHSS) score (R29.7-)” · check together
  • I63 — Cerebral infarction [Use Additional Code](via R29.7.-): “code, if known, to indicate National Institutes of Health Stroke Scale (NIHSS) score (R29.7-)” · check together

Clinical classification (CCSR)

  • CIR020 — Cerebral infarction [CCSR]

Potential MS-DRG

  • DRG 951 — OTHER FACTORS INFLUENCING HEALTH STATUS [MS-DRG]: “OTHER FACTORS INFLUENCING HEALTH STATUS (MDC 23)”

MDC crossing · procedures (1235)

  • MDC 23 — Factors Influencing Health Status and Other Contacts with Health Services [MDC crossing]: “Factors Influencing Health Status and Other Contacts with Health Services — 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.”
  • F003GKZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Audiovisual Equipment [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Audiovisual Equipment — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • F003GMZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Augmentative / Alternative Communication Equipment [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Augmentative / Alternative Communication Equipment — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • F003GPZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Computer [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Computer — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • F003GYZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Other Equipment [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Other Equipment — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • F003GZZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body — grouped in MDC 23, the procedure side of this code's crossing.” · check together
  • and 1230 more

Nearest codes (40)

  • R29 — Other symptoms and signs involving the nervous and musculoskeletal systems [Sibling]
  • R29.703 — NIHSS score 3 [Sibling]
  • R29.704 — NIHSS score 4 [Sibling]
  • R29.705 — NIHSS score 5 [Sibling]
  • R29.706 — NIHSS score 6 [Sibling]
  • R29.707 — NIHSS score 7 [Sibling]
  • R29.708 — NIHSS score 8 [Sibling]
  • R29.709 — NIHSS score 9 [Sibling]
  • and 32 more

Change history (3)

  • FY2027 — Code First note added [Change history]
  • and 2 more

Referenced by Other Codes

Clinical classification (AHRQ CCSR):CIR020 — Cerebral infarction.

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

Potential MS-DRG Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Named in the grouper logic of 1 MS-DRG: DRG 951 (MDC 23).

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

Official ICD-10-CM tabular notes on other codes that name R29.721 or its code family.

4 Use Additional Code instructions: I60 (via R29.7.-), I61 (via R29.7.-), I62 (via R29.7.-), I63 (via R29.7.-).

Nearest Codes in This Family

Official ICD-10-CM classifications closest to R29.721 in its code family, with their registry titles.

View all codes in the R29 family