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R91.1 ICD-10-CM Code: Solitary pulmonary nodule

Compare with another codeCheck this code on a claim

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

Coding at a Glance

Tabular directives
8 inclusion terms · 2 Excludes1

Billable · FY2027A valid, specific ICD-10-CM code, reportable for dates of service in FY2027.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too; the Instructions section marks which is which.

Excludes1Never report with this code
  • abnormal findings on antenatal screening of mother (O28.-)
  • diagnostic abnormal findings classified elsewhere - see Alphabetical Index
IncludesWhat this code covers
  • nonspecific abnormal findings on diagnostic imaging by computerized axial tomography [CAT scan]
  • nonspecific abnormal findings on diagnostic imaging by magnetic resonance imaging [MRI][NMR]
  • nonspecific abnormal findings on diagnostic imaging by positron emission tomography [PET scan]
  • nonspecific abnormal findings on diagnostic imaging by thermography

+4 more in Instructions

Most relevant related codes MedCoder-derived

Read off the official notes above and this code’s own position in the tabular list. Which to report is a documentation question; Compare shows the two side by side.

CompareCheck ClaimView Related Codes

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 205 — OTHER RESPIRATORY SYSTEM DIAGNOSES WITH MCC (MDC 04)
  • MS-DRG 206 — OTHER RESPIRATORY SYSTEM DIAGNOSES WITHOUT MCC (MDC 04)

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.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for R91.1 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on R91.1 itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • nonspecific abnormal findings on diagnostic imaging by computerized axial tomography [CAT scan]
  • nonspecific abnormal findings on diagnostic imaging by magnetic resonance imaging [MRI][NMR]
  • nonspecific abnormal findings on diagnostic imaging by positron emission tomography [PET scan]
  • nonspecific abnormal findings on diagnostic imaging by thermography
  • nonspecific abnormal findings on diagnostic imaging by ultrasound [echogram]
  • nonspecific abnormal findings on diagnostic imaging by X-ray examination

Source: inherited from R90-R94

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Coin lesion lung
  • Solitary pulmonary nodule, subsegmental branch of the bronchial tree

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).

  • abnormal findings on antenatal screening of mother (O28.-) Compare R91.1 vs O28 →
  • diagnostic abnormal findings classified elsewhere - see Alphabetical Index

Source: inherited from R90-R94

Coder workflow for R91.1

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

Before you code R91.1

  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. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with R91.1. 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. 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 R91.1’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.

    ReviewO28

Consider R91.1. Then 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).

Official instructions as workflow

  • Excludes1 — check before selecting R91.1(2 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with R91.1: 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

Coding decision scenarios

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

Documentation: The sign or symptom is documented, and the same record establishes a diagnosis that routinely includes it.

Coding question: Is R91.1 reported in addition to the diagnosis?

Path: Review the documented diagnosis and whether the classification treats this finding as integral to it.

Reason: Signs and symptoms integral to a confirmed diagnosis are not coded separately; those not routinely associated with it may be reported when present (Guidelines I.B.5, I.B.6, I.C.18.b).

Documentation: Both the condition R91.1 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).

ReviewO28

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 R91.1 with…

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

The codes most likely to be picked instead of R91.1 — 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.

  • 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: R91.1 vs O28 →

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.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Solitary pulmonary nodule is a billable ICD-10-CM diagnosis code (R91.1).

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

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-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name R91.1 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 Excludes1 note: R22 — Localized swelling, mass and lump of skin and subcutaneous tissue (via R91.-).

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

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 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 205 (MDC 04), DRG 206 (MDC 04).

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 clinical category (CCSR)

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

R89.4 — Abnormal immunological findings in specimens from other organs, systems and tissues, R89.5 — Abnormal microbiological findings in specimens from other organs, systems and tissues, R89.6 — Abnormal cytological findings in specimens from other organs, systems and tissues, R89.7 — Abnormal histological findings in specimens from other organs, systems and tissues, R89.8 — Other abnormal findings in specimens from other organs, systems and tissues, R89.9 — Unspecified abnormal finding in specimens from other organs, systems and tissues, R90.0 — Intracranial space-occupying lesion found on diagnostic imaging of central nervous system, R90.81 — Abnormal echoencephalogram, R90.82 — White matter disease, unspecified, R90.89 — Other abnormal findings on diagnostic imaging of central nervous system, R91.8 — Other nonspecific abnormal finding of lung field, 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, +183 more

Same Index main term, other category

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

M99.9 — Biomechanical lesion, unspecified (biomechanical), N05.0 — Unspecified nephritic syndrome with minor glomerular abnormality (glomerular, minimal change), N05.1 — Unspecified nephritic syndrome with focal and segmental glomerular lesions (glomerular, focal and segmental), N32.9 — Bladder disorder, unspecified (bladder), N40.2 — Nodular prostate without lower urinary tract symptoms (prostate), N40.3 — Nodular prostate with lower urinary tract symptoms (prostate, with lower urinary tract symptoms), N49.2 — Inflammatory disorders of scrotum (scrotum), N63.0 — Unspecified lump in unspecified breast (breast NEC), N85.9 — Noninflammatory disorder of uterus, unspecified (uterus), N89.8 — Other specified noninflammatory disorders of vagina (vagina), N90.89 — Other specified noninflammatory disorders of vulva and perineum (vulva), O69.5 — Labor and delivery complicated by vascular lesion of cord (vascular, umbilical cord, complicating delivery), Q04.9 — Congenital malformation of brain, unspecified (brain, congenital), Q06.9 — Congenital malformation of spinal cord, unspecified (spinal cord, congenital), Q07.9 — Congenital malformation of nervous system, unspecified (nervous system, congenital), Q24.9 — Congenital malformation of heart, unspecified (cardiac, congenital), R09.89 — Other specified symptoms and signs involving the circulatory and respiratory systems (retrocardiac), R90.0 — Intracranial space-occupying lesion found on diagnostic imaging of central nervous system (intracranial, space-occupying), S43.43 — Superior glenoid labrum lesion (SLAP), T14.8 — Other injury of unspecified body region (vascular, following trauma NEC), +103 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.

Alpha-Fetoprotein (AFP) Test

Contextual Map

Every relationship of R91.1 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 R91.1 with this related code in Claim Check

Hierarchy

Referenced by Excludes1 notes

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 04 — Diseases and Disorders of the Respiratory System[MDC crossing]: “Diseases and Disorders of the Respiratory 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. 4,000 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • Lesion (s) (nontraumatic), coin, lung[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Lesion (s) (nontraumatic), lung (coin)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Nodule, nodular (s), lung, solitary (subsegmental branch of the bronchial tree)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Nodule, nodular (s), pulmonary, solitary (subsegmental branch of the bronchial tree)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Nodule, nodular (s), solitary, lung (subsegmental branch of the bronchial tree)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes

Change history

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

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Indexed Clinical Terms (5)

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.

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 FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 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 — v44 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-derived 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 editorial 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.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 20, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

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. "R91.1 — Solitary pulmonary nodule." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/r91.1-solitary-pulmonary-nodule

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Solitary pulmonary nodule

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, 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 R91.1 in its code family, with their registry titles.

View all codes in the R91 family