M02.30

Reactive arthritis (Reiter's disease) without a documented or determinable joint site — used when the affected anatomical location is not specified in the clinical record.

Verified May 8, 2026 · 6 sources ↓

Status: Billable
Chapter: 13
Related CPT: 7
Region: General

Drawn from CDCICD10DataAAPCIcdlistUnboundmedicine

Documentation tips

What should appear in the chart to support M02.30.

Source · Editorial brief grounded in 6 cited references ↓

Name the triggering infection explicitly — Yersinia enteritis, viral hepatitis, infective endocarditis, etc. — so the mandatory 'code first' underlying disease instruction can be satisfied.
Document the specific joint(s) involved by name and laterality; if any joint is identifiable, a site-specific M02.3x code replaces M02.30.
Record the classic triad components present (urethritis/cervicitis, conjunctivitis, arthritis) and which are active versus resolved at the time of the encounter.
Note the clinical basis for distinguishing reactive arthritis from other inflammatory arthropathies excluded at M02 (e.g., no evidence of Behçet's disease, no direct septic joint).
If the triggering infection has resolved, document that explicitly so the sequencing decision is audit-defensible.

Related CPT procedures

Procedure codes commonly billed with M02.30. 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.

20600 $56.11

Needle aspiration and/or injection of a small joint or bursa — such as a finger or toe joint — performed without ultrasound guidance.

73060 $32.06

Radiologic examination of the humerus (upper arm bone), requiring a minimum of 2 views.

73562 $42.42

Three-view radiographic examination of the knee joint, capturing anteroposterior, lateral, and a third angle such as a sunrise or oblique view.

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 M02.30 and adjacent codes.

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

Defaulting to M02.30 when a joint site is documented — any identified site requires a child code (M02.311–M02.39); M02.30 is only correct when no site can be specified.
Omitting the 'code first' underlying disease code — M02.3x is not a standalone first-listed code when the triggering infection is known and reportable.
Assigning M02.30 for conditions explicitly excluded at M02, such as Behçet's disease (M35.2) or late syphilitic arthritis (A52.77) — the Excludes1 note makes these mutually exclusive.
Confusing M02.30 (unspecified site) with M02.39 (multiple sites) — use M02.39 when polyarthritis involving multiple distinct joints is documented.
Using the non-billable parent M02.3 instead of the billable M02.30 when no site is determinable — M02.3 alone will be rejected as non-specific.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

M02.30 is the unspecified-site code for Reiter's disease (reactive arthritis), a postinfective inflammatory arthropathy historically defined by the triad of urethritis, conjunctivitis, and arthritis following a triggering infection. It sits under parent code M02.3 in the postinfective and reactive arthropathies block (M00–M02). Use M02.30 only when documentation genuinely does not identify which joint or body region is involved. If the site is documented — even as 'unspecified shoulder' or 'left knee' — a more specific M02.3x child code is required.

Because M02.3 carries a mandatory 'Code first underlying disease' instruction, you must sequence the triggering condition ahead of M02.30 when it is known. Recognized triggers include Yersinia enterocolitica enteritis (A04.6), infective endocarditis (I33.0), viral hepatitis (B15–B19), and congenital syphilis with Clutton's joints (A50.5). If the precipitating infection has resolved and no longer meets the definition of a reportable condition, follow the Official Guidelines for Coding and Reporting for sequencing of resolved versus active conditions.

M02.30 groups to MS-DRG v43.0 clusters 545–547 (Connective tissue disorders with/without MCC/CC). The Excludes1 note at M02 blocks several superficially similar diagnoses: Behçet's disease (M35.2), direct joint infection coded elsewhere under M01, postmeningococcal arthritis (A39.84), mumps arthritis (B26.85), rubella arthritis (B06.82), late syphilitic arthritis (A52.77), rheumatic fever (I00), and Charcôt's tabetic arthropathy (A52.16). Do not assign M02.30 when any of those conditions explains the arthropathy.

Sibling codes

Other billable codes under M02.3 (laterality / anatomic variants).

M02.39

Reiter's disease, multiple sites

M02.38

Reiter's disease, vertebrae

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01When is M02.30 the correct code versus a site-specific M02.3x code?

Use M02.30 only when the clinical documentation provides no identifiable joint or body region. As soon as a site — even 'unspecified shoulder' (M02.319) — is documented, the site-specific child code is required. M02.30 is a last resort, not a default.

02Does M02.30 require a secondary code for the triggering infection?

Yes. The 'Code first underlying disease' instruction at M02.3 requires the triggering condition — such as A04.6 (Yersinia enteritis) or B15–B19 (viral hepatitis) — to be sequenced before M02.30 when that condition is known and currently reportable.

03Can M02.30 be used alongside M35.2 (Behçet's disease)?

No. The Excludes1 note at M02 prohibits assigning any M02 code with M35.2. These diagnoses are mutually exclusive — Behçet's disease has its own code and cannot coexist with a reactive arthropathy code in the same claim.

04How does M02.30 differ from M02.39?

M02.39 is used when reactive arthritis/Reiter's disease is documented at multiple distinct joint sites. M02.30 is for encounters where the affected site is genuinely unspecified or undocumentable — not for polyarticular disease.

05Is 'reactive arthritis' an acceptable documentation term to support M02.30?

Yes. The ICD-10-CM tabular includes 'Reactive arthritis' as an applicable synonym under M02.3, and M02.30 is its unspecified-site billable child. Ensure the note distinguishes it from the Excludes1 conditions before assigning the code.

06What MS-DRG does M02.30 map to?

M02.30 groups to MS-DRG v43.0 clusters 545 (Connective tissue disorders with MCC), 546 (with CC), and 547 (without CC/MCC). Accurate capture of comorbidities and complications drives the correct DRG assignment and reimbursement level.

07Can M02.30 be used as a primary diagnosis on an orthopedic claim?

Only if the triggering infection is resolved or unknown. When an active underlying disease is identifiable and still reportable, it must be sequenced first per the 'Code first' instruction. Claiming M02.30 as primary when an active trigger is documented is a sequencing error.

Sources & references

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

Mira AI Scribe

The Mira AI Scribe captures the affected joint(s) with laterality, the identified or suspected triggering infection (type, date, treatment status), and the clinical features supporting reactive arthritis — urethritis, conjunctivitis, inflammatory joint findings — directly from the encounter note. That detail drives selection of a site-specific M02.3x child code over M02.30 and satisfies the mandatory 'code first' sequencing requirement, preventing payer rejection for non-specific coding and protecting against audit exposure from a missing primary diagnosis.

See how Mira captures M02.30 documentation