K52.839 ICD-10-CM Code: Microscopic colitis, unspecified

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for K52.839 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 K52.839 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for K52.839

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

Before you code K52.839

1. Unspecified does not mean incorrect. When the record gives no greater specificity, K52.839 may be the appropriate code. Check the record for detail that supports a more specific sibling. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

   ReviewK52.831, K52.832, K52.838

   See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with K52.839. 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 record document the detail a more specific sibling code needs?
   Yes → Review the specific siblings in this subcategory.
   No → Continue — K52.839 is appropriate when the documentation goes no further.

   ReviewK52.831, K52.832, K52.838

2. Does the documentation support a condition named in K52.839’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.

   ReviewK58, K59.3

Consider K52.839. 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).

Any detail beyond this code’s title

What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

• Excludes1 — check before selecting K52.839(2 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with K52.839: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareK58, K59.3

  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

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.

• Colitis (acute) (catarrhal) (chronic) (noninfective) (hemorrhagic), microscopic

Official Coding Guidelines

No excerpt in the ICD-10-CM Official Guidelines names this code specifically. Its chapter carries only this chapter-wide note:

Don’t confuse K52.839 with…

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

The codes most likely to be picked instead of K52.839 — 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.

• K58— 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 irritable bowel syndrome moves the case to K58; the two are not reported together unless documented as unrelated.

  Full comparison: K52.839 vs K58 →

• K59.3— 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 megacolon moves the case to K59.3; the two are not reported together unless documented as unrelated.

  Full comparison: K52.839 vs K59.3 →

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.

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

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 391 (MDC 06), DRG 392 (MDC 06).

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

Clinical classification (AHRQ CCSR):DIG022 — Noninfectious gastroenteritis (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 (Noninfectious gastroenteritis).

K52.0 — Gastroenteritis and colitis due to radiation, K52.1 — Toxic gastroenteritis and colitis, K52.2 — Allergic and dietetic gastroenteritis and colitis, K52.21 — Food protein-induced enterocolitis syndrome, K52.22 — Food protein-induced enteropathy, K52.29 — Other allergic and dietetic gastroenteritis and colitis, K52.3 — Indeterminate colitis, K52.81 — Eosinophilic gastritis or gastroenteritis, K52.82 — Eosinophilic colitis, K52.831 — Collagenous colitis, K52.832 — Lymphocytic colitis, K52.838 — Other microscopic colitis, K52.89 — Other specified noninfective gastroenteritis and colitis, K52.9 — Noninfective gastroenteritis and colitis, unspecified

Same Index main term, other category

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

K51.80 — Other ulcerative colitis without complications (ulcerative, specified type NEC), K51.811 — Other ulcerative colitis with rectal bleeding (ulcerative, specified type NEC, with, complication, rectal bleeding), K51.812 — Other ulcerative colitis with intestinal obstruction (ulcerative, specified type NEC, with, complication, obstruction), K51.813 — Other ulcerative colitis with fistula (ulcerative, specified type NEC, with, complication, fistula), K51.814 — Other ulcerative colitis with abscess (ulcerative, specified type NEC, with, complication, abscess), K51.818 — Other ulcerative colitis with other complication (ulcerative, specified type NEC, with, complication, specified complication NEC), K51.819 — Other ulcerative colitis with unspecified complications (ulcerative, specified type NEC, with, complication), K51.90 — Ulcerative colitis, unspecified, without complications (ulcerative), K51.911 — Ulcerative colitis, unspecified with rectal bleeding (ulcerative, with, complication, rectal bleeding), K51.912 — Ulcerative colitis, unspecified with intestinal obstruction (ulcerative, with, complication, obstruction), K51.913 — Ulcerative colitis, unspecified with fistula (ulcerative, with, complication, fistula), K51.914 — Ulcerative colitis, unspecified with abscess (ulcerative, with, complication, abscess), K51.918 — Ulcerative colitis, unspecified with other complication (ulcerative, with, complication, specified complication NEC), K51.919 — Ulcerative colitis, unspecified with unspecified complications (ulcerative, with, complication), K55.039 — Acute (reversible) ischemia of large intestine, extent unspecified (ischemic, acute), K55.1 — Chronic vascular disorders of intestine (ischemic, chronic), K55.9 — Vascular disorder of intestine, unspecified (ischemic), K58.0 — Irritable bowel syndrome with diarrhea (spastic, with diarrhea), K58.9 — Irritable bowel syndrome, unspecified (spastic), Z71.3 — Dietary counseling and surveillance (dietary counseling and surveillance), +22 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.

Fecal Occult Blood Test (FOBT), Gamma-glutamyl Transferase (GGT) Test, HIV Screening Test, Iron Panel

Contextual Map

Every relationship of K52.839 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

• K00-K95 — Chapter 11: Diseases of the Digestive System (K00-K95) (K00-K95)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K50-K52 — Noninfective enteritis and colitis[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Clinical classification (CCSR)

• DIG022 — Noninfectious gastroenteritis[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• DRG 391 — ESOPHAGITIS, GASTROENTERITIS AND MISCELLANEOUS DIGESTIVE DISORDERS WITH MCC[MS-DRG]: “ESOPHAGITIS, GASTROENTERITIS AND MISCELLANEOUS DIGESTIVE DISORDERS WITH MCC (MDC 06)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 392 — ESOPHAGITIS, GASTROENTERITIS AND MISCELLANEOUS DIGESTIVE DISORDERS WITHOUT MCC[MS-DRG]: “ESOPHAGITIS, GASTROENTERITIS AND MISCELLANEOUS DIGESTIVE DISORDERS WITHOUT MCC (MDC 06)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 06 — Diseases and Disorders of the Digestive System[MDC crossing]: “Diseases and Disorders of the Digestive 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. 5,744 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Colitis (acute) (catarrhal) (chronic) (noninfective) (hemorrhagic), microscopic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (17)

• K52 — Other and unspecified noninfective gastroenteritis and colitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K52.0 — Gastroenteritis and colitis due to radiation[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K52.1 — Toxic gastroenteritis and colitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K52.2 — Allergic and dietetic gastroenteritis and colitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K52.21 — Food protein-induced enterocolitis syndrome[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K52.22 — Food protein-induced enteropathy[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K52.29 — Other allergic and dietetic gastroenteritis and colitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K52.3 — Indeterminate colitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 9 more

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 K52.839 in its code family, with their registry titles.

• K52.3 — Indeterminate colitis
• K52.8 — Other specified noninfective gastroenteritis and colitis
• K52.81 — Eosinophilic gastritis or gastroenteritis
• K52.82 — Eosinophilic colitis
• K52.83 — Microscopic colitis
• K52.831 — Collagenous colitis
• K52.832 — Lymphocytic colitis
• K52.838 — Other microscopic colitis
• K52.89 — Other specified noninfective gastroenteritis and colitis
• K52.9 — Noninfective gastroenteritis and colitis, unspecified

View all codes in the K52 family