M12.30

Palindromic rheumatism with no documented joint site — use only when the affected joint(s) cannot be identified from the encounter documentation.

Verified May 8, 2026 · 5 sources ↓

Status: Billable
Chapter: 13
Related CPT: 8
Region: General

Drawn from CDCICDAAPCCMS

Documentation tips

What should appear in the chart to support M12.30.

Source · Editorial brief grounded in 5 cited references ↓

Record which specific joint(s) were symptomatic at the time of the encounter — even if the attack has resolved, the joint site should appear in the note to support a site-specific code over M12.30.
Document the episodic, self-resolving nature of the inflammation explicitly; this distinguishes palindromic rheumatism from other inflammatory arthropathies and supports the M12.3x category over rheumatoid arthritis codes.
If imaging or aspiration was performed during an acute episode, include the joint name and side in both the clinical findings and the impression — this directly enables laterality coding.
Note the duration and frequency of episodes; this supports medical necessity for ongoing management visits and differentiates palindromic rheumatism from acute monoarthritis.
If the patient is being monitored for potential conversion to rheumatoid arthritis, document that status separately — it may warrant an additional code but does not change M12.30 assignment.

Related CPT procedures

Procedure codes commonly billed with M12.30. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

20610 $68.81

Aspiration and/or injection of a major joint or bursa (shoulder, hip, knee, or subacromial bursa) performed without ultrasound guidance.

20611 $104.21

Aspiration or injection of a major joint or bursa performed under real-time ultrasound guidance, with permanent image documentation.

73221 $205.08

MRI of any upper extremity joint — shoulder, elbow, or wrist — performed without contrast material.

73221 $205.08

MRI of any upper extremity joint — shoulder, elbow, or wrist — performed without contrast material.

72148 $191.72

Non-contrast MRI of the lumbar spine used to evaluate disc pathology, spinal stenosis, nerve root compression, and other structural abnormalities without administration of contrast material.

99213 $95.19

Established patient office or outpatient visit requiring 20–29 minutes of total time or low-complexity medical decision-making.

99214 $135.61

Office visit for an established patient requiring moderate-complexity medical decision making (MDM), or 30–39 minutes of total provider time on the date of service.

99215 $192.39

Highest-level office or outpatient E/M visit for an established patient, qualifying via high-complexity medical decision making or 40–54 minutes of total provider time on the date of service.

Common coding pitfalls

The recurring mistakes coders make with M12.30 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

Defaulting to M12.30 when a joint was actually documented — review the note for any mention of a specific joint before accepting the unspecified-site code; site-specific M12.31x–M12.39x codes are always preferred.
Confusing palindromic rheumatism with early rheumatoid arthritis (M05–M06): do not substitute an RA code unless the provider has documented a confirmed RA diagnosis; palindromic rheumatism is a distinct entity until proven otherwise.
Assigning M12.30 for bilateral or multi-joint attacks without exploring M12.39x (other specified site) or stacking multiple site-specific codes when the note documents specific joints on both sides.
Overlooking the Type 1 Excludes at the M12 category level — arthrosis should be coded to M15–M19, not under M12.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M12.30 captures palindromic rheumatism when the provider has not specified which joint is involved, or when documentation is insufficient to assign a site-specific code. Palindromic rheumatism is a pattern of episodic, self-resolving joint inflammation — attacks typically last hours to days before completely remitting, with no residual joint damage between episodes. Because the condition is migratory and unpredictable, documentation often reflects the pattern rather than a single consistent joint.

The M12.3x subcategory offers site-specific codes covering the shoulder (M12.31x), elbow (M12.32x), wrist (M12.33x), and other anatomical sites with full laterality granularity (1 = right, 2 = left, 9 = unspecified side). M12.30 is the fallback only when no site is identifiable — not the default when the provider simply hasn't charted laterality yet. If a joint was mentioned during the visit, push for the site-specific code.

Palindromicc rheumatism falls under the parent category M12 (Other and unspecified arthropathy). Note the Type 1 Excludes at M12: arthrosis (M15–M19) and cricoarytenoid arthropathy (J38.7) are excluded and must not be coded here. M12.30 groups into MS-DRG v43.0 DRGs 553 (with MCC) and 554 (without MCC) for inpatient purposes.

Sibling codes

Other billable codes under M12.3 (laterality / anatomic variants).

M12.38

Palindromic rheumatism, other specified site

M12.39

Palindromic rheumatism, multiple sites

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01When is M12.30 the correct code versus a site-specific M12.3xx code?

Use M12.30 only when the encounter documentation genuinely does not identify any affected joint. If the provider named a joint — even in passing — assign the site-specific code (e.g., M12.341 for the right hand). M12.30 is a last resort, not a shortcut.

02Can M12.30 be used for an attack that has already resolved by the time of the visit?

Yes. Palindromic rheumatism is characterized by self-resolving attacks, so coding a resolved episode at a follow-up visit is appropriate. Apply the same site-specificity rules — if the patient describes which joint was affected, document and code that site.

03Should palindromic rheumatism be coded with a rheumatoid arthritis code if the patient is at risk for RA conversion?

No. Do not add an RA code speculatively. Code only confirmed diagnoses. If RA is later confirmed, transition to the appropriate M05 or M06 code at that point and stop using M12.3x.

04Is M12.30 valid for inpatient claims?

Yes. M12.30 groups to MS-DRG 553 (with MCC) or 554 (without MCC) under MS-DRG v43.0. It is a billable code in both inpatient and outpatient settings.

05Can multiple M12.3x codes be assigned in one encounter if several joints were affected during a single attack?

Yes. If the provider documents involvement of more than one specific joint during the same episode, assign a separate M12.3x code for each documented site. Do not collapse multi-joint attacks into M12.30 simply because more than one joint is involved.

06Does palindromic rheumatism require an Excludes note check before coding?

Yes. The M12 category carries a Type 1 Excludes for arthrosis (M15–M19) and cricoarytenoid arthropathy (J38.7). If the documentation points to osteoarthritis rather than inflammatory arthropathy, reroute to the appropriate M15–M19 code — those cannot be coded simultaneously with M12.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

01CDC ICD-10-CM Tabular List 2026, category M12, http://stacks.cdc.gov/view/cdc/250974
02ICD10data.com 2026 code M12.30, https://www.icd10data.com/ICD10CM/Codes/M00-M99/M05-M14/M12-/M12.30
03AAPC Codify, M12.30, https://www.aapc.com/codes/icd-10-codes/M12.30
04CMS ICD-10-CM Official Guidelines FY2026, http://stacks.cdc.gov/view/cdc/250974
05CDC NCHS ICD-10-CM, https://www.cdc.gov/nchs/icd/icd-10-cm/index.html

Mira AI Scribe

Mira AI Scribe captures joint name, laterality, episode duration, and spontaneous resolution from the encounter narrative — the exact documentation needed to elevate M12.30 to a site-specific M12.31x–M12.39x code. Without that capture, the claim lands on the least-specific code in the subcategory, which can trigger specificity-based downcoding or payer requests for additional documentation.

See how Mira captures M12.30 documentation