R92.331 ICD-10-CM Code: Mammographic heterogeneous density, right breast

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for R92.331 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 R92.331 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for R92.331

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

Before you code R92.331

1. Check whether an established diagnosis that explains this sign or symptom is documented. If one is, review whether the documented diagnosis changes the coding pathway: a symptom that is integral to a confirmed diagnosis is not reported separately, while one not routinely associated with it may be. Signs and symptoms are reported when no definitive diagnosis is established (Guidelines I.B.4, I.B.5, I.B.6, I.C.18.b).

   Guide: Symptom code vs confirmed diagnosis →

2. Laterality is coded in this family. Confirm the side documented — right, left, or bilateral — and select the matching code (this page’s code: right). The unspecified-side code applies only when the record states no side. Laterality is assigned from the documented side; where a bilateral code exists and both sides are documented, it is used instead of two unilateral codes (Guidelines I.B.13).

   ReviewR92.332 · left

   Guide: Laterality coding →

3. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with R92.331. 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. Is an established diagnosis that explains this sign or symptom documented?
   Yes → Review whether the documented diagnosis changes the coding pathway: a symptom integral to it is not reported separately.
   No → Continue — the sign or symptom code stands when no definitive diagnosis is established.
2. Does the documentation support a condition named in R92.331’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.

   ReviewO28

3. Is the side documented?
   Yes → Select the code for the documented side (or the bilateral code when both sides are documented and one exists).
   No → Use the unspecified-side code only when the record states no side; a query is the alternative.

   ReviewR92.332 · left

Consider R92.331. Then 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).

Laterality

Right, left or bilateral as documented; unspecified only when the record states no side (Guidelines I.B.13).

Official instructions as workflow

• Excludes1 — check before selecting R92.331(2 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with R92.331: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareO28

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

• 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.

  ReviewR92.2

  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.

Don’t confuse R92.331 with…

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

The codes most likely to be picked instead of R92.331 — 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.

• O28— 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 abnormal findings on antenatal screening of mother moves the case to O28; the two are not reported together unless documented as unrelated.

  Full comparison: R92.331 vs O28 →

• R92.332— Laterality relationship (Review)

  Same condition; these differ only in which side is documented.

  The same condition on the other side; the documented side decides, and a bilateral code, where one exists, replaces the pair when both sides are documented.

  What moves you there: A documented left side moves the case to R92.332.

  Full comparison: R92.331 vs R92.332 →

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. Laterality is coded in this family. Confirm the documented side matches the code — the opposite-side siblings are in the relationships section. See the opposite-side sibling codes
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. 2 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 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

• No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

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 R92.331 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: R22 — Localized swelling, mass and lump of skin and subcutaneous tissue (via R92.-).

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

Referenced by 1 Excludes2 note: N64.5 — Other signs and symptoms in breast (via R92.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 2 MS-DRGs: DRG 600 (MDC 09), DRG 601 (MDC 09).

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

Clinical classification (AHRQ CCSR):SYM017 — Abnormal findings without diagnosis (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 condition, opposite side

Same category and title, differing only in which side of the body is affected.

R92.332 — Mammographic heterogeneous density, left breastCompare R92.331 vs R92.332 →

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Abnormal findings without diagnosis).

R92.0 — Mammographic microcalcification found on diagnostic imaging of breast, R92.1 — Mammographic calcification found on diagnostic imaging of breast, R92.2 — Inconclusive mammogram, R92.30 — Dense breasts, unspecified, R92.311 — Mammographic fatty tissue density, right breast, R92.312 — Mammographic fatty tissue density, left breast, R92.313 — Mammographic fatty tissue density, bilateral breasts, R92.321 — Mammographic fibroglandular density, right breast, R92.322 — Mammographic fibroglandular density, left breast, R92.323 — Mammographic fibroglandular density, bilateral breasts, R92.332 — Mammographic heterogeneous density, left breast, R92.333 — Mammographic heterogeneous density, bilateral breasts, R92.341 — Mammographic extreme density, right breast, R92.342 — Mammographic extreme density, left breast, R92.343 — Mammographic extreme density, bilateral breasts, R92.8 — Other abnormal and inconclusive findings on diagnostic imaging of breast, R93.0 — Abnormal findings on diagnostic imaging of skull and head, not elsewhere classified, R93.1 — Abnormal findings on diagnostic imaging of heart and coronary circulation, R93.2 — Abnormal findings on diagnostic imaging of liver and biliary tract, R93.3 — Abnormal findings on diagnostic imaging of other parts of digestive tract, +183 more

Same Index main term, other category

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

E30.1 — Precocious puberty (buds), J98.4 — Other disorders of lung (lung), N63.0 — Unspecified lump in unspecified breast (nodule), P96.89 — Other specified conditions originating in the perinatal period (buds, in newborn)

Contextual Map

Every relationship of R92.331 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 R92.331 with these 2 related codes in Claim Check

Hierarchy

• R00-R99 — Chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99) (R00-R99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R90-R94 — Abnormal findings on diagnostic imaging and in function studies, without diagnosis[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

• R22 — Localized swelling, mass and lump of skin and subcutaneous tissue[Excludes1](via R92.-): “abnormal findings on diagnostic imaging (R90-R93)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

• N64.5 — Other signs and symptoms in breast[Excludes2](via R92.-): “abnormal findings on diagnostic imaging of breast (R92.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• SYM017 — Abnormal findings without diagnosis[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• DRG 600 — NON-MALIGNANT BREAST DISORDERS WITH CC/MCC[MS-DRG]: “NON-MALIGNANT BREAST DISORDERS WITH CC/MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 601 — NON-MALIGNANT BREAST DISORDERS WITHOUT CC/MCC[MS-DRG]: “NON-MALIGNANT BREAST DISORDERS WITHOUT CC/MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 09 — Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast[MDC crossing]: “Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast — 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. 7,376 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Nearest codes (22)

• R92 — Abnormal and inconclusive findings on diagnostic imaging of breast[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R92.0 — Mammographic microcalcification found on diagnostic imaging of breast[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R92.1 — Mammographic calcification found on diagnostic imaging of breast[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R92.2 — Inconclusive mammogram[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R92.3 — Mammographic density found on imaging of breast[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R92.30 — Dense breasts, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R92.31 — Mammographic fatty tissue density of breast[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R92.311 — Mammographic fatty tissue density, right breast[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 14 more

Change history

• FY2024 — Added to the code set[Change history]— CMS release files (code change ledger) · icd10cm-fy2024

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

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 R92.331 in its code family, with their registry titles.

• R92.32 — Mammographic fibroglandular density of breast
• R92.321 — Mammographic fibroglandular density, right breast
• R92.322 — Mammographic fibroglandular density, left breast
• R92.323 — Mammographic fibroglandular density, bilateral breasts
• R92.33 — Mammographic heterogeneous density of breast
• R92.332 — Mammographic heterogeneous density, left breast
• R92.333 — Mammographic heterogeneous density, bilateral breasts
• R92.34 — Mammographic extreme density of breast
• R92.341 — Mammographic extreme density, right breast
• R92.342 — Mammographic extreme density, left breast

View all codes in the R92 family