M13
Non-Billable

Other arthritis

Non-Billable / Non-Specific Code

What is Other arthritis?

ICD-10-CM M13 is the diagnosis code for Other arthritis. This code falls under the section "Inflammatory polyarthropathies" within Chapter 13 — Diseases of the musculoskeletal system and connective tissue (M00-M99). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.

⛔ Excludes1

Coding Guidelines for M13

⛔ Type 1 Excludes (Never code together)

The following conditions should never be coded at the same time as M13. They are mutually exclusive:

  • arthrosis (M15-M19)
  • osteoarthritis (M15-M19)

ICD-10-CM Code Hierarchy

Understanding where M13 sits in the ICD-10-CM classification helps ensure proper coding:

Sub-Codes 3 entries
M13.0Polyarthritis, unspecifiedBillableM13.1Monoarthritis, not elsewhere classifiedNon-BillableM13.10Monoarthritis, not elsewhere classified, unspecified siteBillableM13.11Monoarthritis, not elsewhere classified, shoulderNon-BillableM13.111Monoarthritis, not elsewhere classified, right shoulderBillableM13.112Monoarthritis, not elsewhere classified, left shoulderBillableM13.119Monoarthritis, not elsewhere classified, unspecified shoulderBillableM13.12Monoarthritis, not elsewhere classified, elbowNon-BillableM13.121Monoarthritis, not elsewhere classified, right elbowBillableM13.122Monoarthritis, not elsewhere classified, left elbowBillableM13.129Monoarthritis, not elsewhere classified, unspecified elbowBillableM13.13Monoarthritis, not elsewhere classified, wristNon-BillableM13.131Monoarthritis, not elsewhere classified, right wristBillableM13.132Monoarthritis, not elsewhere classified, left wristBillableM13.139Monoarthritis, not elsewhere classified, unspecified wristBillableM13.14Monoarthritis, not elsewhere classified, handNon-BillableM13.141Monoarthritis, not elsewhere classified, right handBillableM13.142Monoarthritis, not elsewhere classified, left handBillableM13.149Monoarthritis, not elsewhere classified, unspecified handBillableM13.15Monoarthritis, not elsewhere classified, hipNon-BillableM13.151Monoarthritis, not elsewhere classified, right hipBillableM13.152Monoarthritis, not elsewhere classified, left hipBillableM13.159Monoarthritis, not elsewhere classified, unspecified hipBillableM13.16Monoarthritis, not elsewhere classified, kneeNon-BillableM13.161Monoarthritis, not elsewhere classified, right kneeBillableM13.162Monoarthritis, not elsewhere classified, left kneeBillableM13.169Monoarthritis, not elsewhere classified, unspecified kneeBillableM13.17Monoarthritis, not elsewhere classified, ankle and footNon-BillableM13.171Monoarthritis, not elsewhere classified, right ankle and footBillableM13.172Monoarthritis, not elsewhere classified, left ankle and footBillableM13.179Monoarthritis, not elsewhere classified, unspecified ankle and footBillableM13.8Other specified arthritisNon-BillableM13.80Other specified arthritis, unspecified siteBillableM13.81Other specified arthritis, shoulderNon-BillableM13.811Other specified arthritis, right shoulderBillableM13.812Other specified arthritis, left shoulderBillableM13.819Other specified arthritis, unspecified shoulderBillableM13.82Other specified arthritis, elbowNon-BillableM13.821Other specified arthritis, right elbowBillableM13.822Other specified arthritis, left elbowBillableM13.829Other specified arthritis, unspecified elbowBillableM13.83Other specified arthritis, wristNon-BillableM13.831Other specified arthritis, right wristBillableM13.832Other specified arthritis, left wristBillableM13.839Other specified arthritis, unspecified wristBillableM13.84Other specified arthritis, handNon-BillableM13.841Other specified arthritis, right handBillableM13.842Other specified arthritis, left handBillableM13.849Other specified arthritis, unspecified handBillableM13.85Other specified arthritis, hipNon-BillableM13.851Other specified arthritis, right hipBillableM13.852Other specified arthritis, left hipBillableM13.859Other specified arthritis, unspecified hipBillableM13.86Other specified arthritis, kneeNon-BillableM13.861Other specified arthritis, right kneeBillableM13.862Other specified arthritis, left kneeBillableM13.869Other specified arthritis, unspecified kneeBillableM13.87Other specified arthritis, ankle and footNon-BillableM13.871Other specified arthritis, right ankle and footBillableM13.872Other specified arthritis, left ankle and footBillableM13.879Other specified arthritis, unspecified ankle and footBillableM13.88Other specified arthritis, other siteBillableM13.89Other specified arthritis, multiple sitesBillable
Related Codes

Frequently Asked Questions

Is M13 a billable ICD-10-CM code?

No, M13 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.

What does M13 mean?

M13 is the ICD-10-CM diagnosis code for "Other arthritis". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.

What section is M13 in?

M13 is located in Section M05-M14 — "Inflammatory polyarthropathies" within Chapter 13 of the ICD-10-CM Tabular List.

What are the sub-codes of M13?

M13 has 3 sub-code(s) that provide more specific detail: M13.0, M13.1, M13.8.

When should I use M13?

Use M13 when the patients documented diagnosis matches "Other arthritis" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.

People Also Ask

What is the ICD-10 code for Other arthritis?

The ICD-10-CM code for Other arthritis is M13.

Can M13 be used for primary diagnosis?

No, M13 is non-billable. Use a more specific sub-code for primary diagnosis billing.

What chapter is M13 in?

M13 is in Chapter 13 of the ICD-10-CM Tabular List.

What conditions are excluded from M13?

Type 1 Excludes for M13 include: arthrosis (M15-M19); osteoarthritis (M15-M19).

Is M13 valid for 2026?

Yes, M13 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.

See Also

← PreviousM12.9Arthropathy, unspecifiedNext →M13.0Polyarthritis, unspecified
Code Details
M13
Other arthritis
Non-Billable / Non-Specific Code
13 — Diseases of the musculoskeletal system and connective tissue (M00-M99)
M05-M14 — Inflammatory polyarthropathies
2026 ICD-10-CM