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M46.40 ICD-10-CM Code: Discitis, unspecified, site unspecified

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

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 v43, Appendix B.

  • MS-DRG 551 — MEDICAL BACK PROBLEMS WITH MCC (MDC 08)
  • MS-DRG 552 — MEDICAL BACK PROBLEMS WITHOUT MCC (MDC 08)

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.

Coder workflow for M46.40

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

Before you code M46.40

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, M46.40 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).

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

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 — M46.40 is appropriate when the documentation goes no further.

Consider M46.40. 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.

Coding decision scenarios

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

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the subcategory for a sibling that names the missing detail.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

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.

Code Overview

Discitis, unspecified, site unspecified is a billable ICD-10-CM diagnosis code (M46.40).

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

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.

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 M46.40 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 6 Excludes1 notes across 2 chapters: G55 — Nerve root and plexus compressions in diseases classified elsewhere (via M46.-), M50 — Cervical disc disorders (via M46.4.-), M50-M54 — Other dorsopathies (M50-M54) (via M46.4.-), M51 — Thoracic, thoracolumbar, and lumbosacral intervertebral disc disorders (via M46.4.-), M53 — Other and unspecified dorsopathies, not elsewhere classified (via M46.4.-), M54 — Dorsalgia (via M46.4.-).

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

Referenced by 7 Excludes2 notes: M20 — Acquired deformities of fingers and toes (via M46.-), M20-M25 — Other joint disorders (M20-M25) (via M46.-), M21 — Other acquired deformities of limbs (via M46.-), M22 — Disorder of patella (via M46.-), M23 — Internal derangement of knee (via M46.-), M24 — Other specific joint derangements (via M46.-), M25 — Other joint disorder, not elsewhere classified (via M46.-).

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 551 (MDC 08), DRG 552 (MDC 08).

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

Clinical classification (AHRQ CCSR):MUS011 — Spondylopathies/spondyloarthropathy (including infective) (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 (Spondylopathies/spondyloarthropathy (including infective)).

+361 more

Contextual Map

Every relationship of M46.40 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 M46.40 with these 13 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 08 — Diseases and Disorders of the Musculoskeletal System and Connective Tissue[MDC crossing]: “Diseases and Disorders of the Musculoskeletal System and Connective Tissue — 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. 18,508 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

  • Discitis, diskitis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (40)

Change history

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

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

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. "M46.40 — Discitis, unspecified, site unspecified." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/m46.40-discitis-unspecified-site-unspecified

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Discitis, unspecified, site unspecified

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), 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 M46.40 in its code family, with their registry titles.

View all codes in the M46 family