ICD-10-CM · Other

M08.2A

Juvenile rheumatoid arthritis with systemic onset affecting a documented but anatomically atypical joint site not captured by the standard laterality-based subcodes in the M08.2x series.

Verified May 8, 2026 · 8 sources ↓

Status: Billable
Chapter: 13
Related CPT: 14
Region: Other

Drawn from CDCICD10DataAAPCCMSCodingbillingsolutions

Documentation tips

What should appear in the chart to support M08.2A.

Source · Editorial brief grounded in 8 cited references ↓

Provider must name the specific joint affected (e.g., temporomandibular, sternoclavicular) — 'other site' in the diagnosis requires a documented site in the note.
Confirm age of onset is documented as under 16; M08.2A is invalid for adult-onset Still's disease, which maps to M06.1-.
Record systemic features that distinguish sJIA: quotidian fever, salmon-colored rash, hepatosplenomegaly, serositis, or lymphadenopathy, as these support the 'systemic onset' specificity.
If Crohn's disease or ulcerative colitis is an associated condition, document the relationship explicitly so the coder can add the K50.- or K51.- code per tabular instruction.
Note any imaging (X-ray, MRI, ultrasound) of the involved joint to support degenerative or inflammatory findings at the specified site.
Document that the diagnosis meets JIA classification criteria (e.g., ILAR criteria) to distinguish from reactive or infectious arthritis, which code elsewhere.

Related CPT procedures

Procedure codes commonly billed with M08.2A. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

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.

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.

73030 $35.74

Radiologic examination of the shoulder requiring a minimum of two views, reported as a single unit regardless of how many views are obtained.

73070 $29.39

Radiographic examination of the elbow joint using a minimum of 2 views to evaluate bone structure and surrounding tissues.

73100 $34.40

Radiologic examination of the wrist with a minimum of two views.

73130 $38.08

Radiographic examination of the hand requiring a minimum of three views.

73560 $34.40

Radiologic examination of the knee joint, one or two views, unilateral.

73564 $49.43

Radiologic examination of the knee consisting of four or more views, including oblique and tunnel projections, for a complete diagnostic workup.

73610 $37.07

Radiologic examination of the ankle joint requiring a minimum of three views, used to evaluate bone structure, alignment, and soft-tissue abnormalities.

72100 $40.42

Radiologic examination of the lumbosacral spine capturing two or three views, used to evaluate the lumbar vertebrae and sacrum for injury, degeneration, or structural abnormality.

96372 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M08.2A and adjacent codes.

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

Defaulting to M08.29 (unspecified site) when the provider has actually named an atypical joint — M08.2A is the correct code when a site is documented but doesn't match the standard subcodes.
Applying M08.2A to adult patients: the Excludes1 note at M08.2 prohibits its use for adult-onset Still's disease (M06.1-), making age at onset a required verification step.
Omitting the 'Code also' secondary diagnosis for associated IBD (K50.- or K51.-) when it's documented in the chart.
Confusing M08.2A with M08.09 (unspecified JRA, multiple sites) — systemic-onset JIA is a distinct subtype from oligoarticular or polyarticular JIA and must be coded under M08.2x, not M08.0x or M08.3.
Using M08.2A for psoriatic juvenile arthropathy or juvenile dermatomyositis — both are Excludes1 conditions that have their own codes (L40.54 and M33.0-, respectively).

Clinical context

Source · Editorial summary grounded in 8 cited references ↓

M08.2A applies when a pediatric patient (onset before age 16) has systemic-onset juvenile idiopathic arthritis (sJIA) — formerly called Still's disease in children — with joint involvement at a site that doesn't fit the named locations in the M08.2x series (shoulder, elbow, wrist, hand, hip, knee, ankle/foot, vertebrae). Examples include the temporomandibular joint, sternoclavicular joint, or acromioclavicular joint. The provider must specifically document the affected site; 'other specified' is not a fallback for insufficient documentation — it's a precision code for a named but unlisted location.

The parent category M08.2 carries a mandatory Excludes1 note for adult-onset Still's disease (M06.1-), which is coded entirely separately. If the patient is an adult, M08.2A is wrong regardless of the clinical presentation. The M08 category as a whole excludes arthropathy in Whipple's disease (M14.8), Felty's syndrome (M05.0), juvenile dermatomyositis (M33.0-), and psoriatic juvenile arthropathy (L40.54) — none of those map here.

If an associated underlying condition such as Crohn's disease (K50.-) or ulcerative colitis (K51.-) is present, code it additionally per the tabular 'Code also' instruction. M08.2A sits adjacent to M08.29 (unspecified site) — use M08.29 only when the joint location is genuinely undocumented, not when it's unusual. The unspecified code is an audit risk and should be avoided when the clinical note names the joint.

Sibling codes

Other billable codes under M08.2 (laterality / anatomic variants).

M08.29

Juvenile rheu arthritis w systemic onset, multiple sites

M08.28

Juvenile rheumatoid arthritis with systemic onset, vertebrae

M08.20

Juvenile rheumatoid arthritis with systemic onset, unsp site

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 8 cited references ↓

01When does M08.2A apply instead of M08.29?

Use M08.2A when the provider documents a specific joint that isn't covered by the named M08.2x subcodes (shoulder, elbow, wrist, hand, hip, knee, ankle/foot, vertebrae). Use M08.29 only when the affected site is genuinely not documented anywhere in the record.

02Can M08.2A be used for an adult patient with Still's disease?

No. The Excludes1 note at M08.2 explicitly prohibits this. Adult-onset Still's disease codes to M06.1-. Verify that onset occurred before age 16 before assigning any M08.2x code.

03What secondary codes should be added with M08.2A?

If the patient has Crohn's disease, add the appropriate K50.- code. If ulcerative colitis is present, add the appropriate K51.- code. The tabular 'Code also' instruction at M08 makes this mandatory when those conditions are documented.

04Is M08.2A the right code for TMJ involvement in a child with sJIA?

Yes. The temporomandibular joint is not listed among the standard M08.2x site subcodes, so documented TMJ arthritis in the context of systemic-onset JIA maps to M08.2A as an 'other specified site.'

05How does M08.2A differ from M08.09?

M08.09 is for unspecified juvenile rheumatoid arthritis (not systemic-onset) at multiple sites under the M08.0x subtype. M08.2A is specifically for the systemic-onset subtype (sJIA/Still's disease in children) at an atypical but named single site. They are different disease subtypes and are not interchangeable.

06Does psoriatic juvenile arthropathy involving an atypical joint also use M08.2A?

No. Psoriatic juvenile arthropathy is an Excludes1 condition at the M08 category level and maps to L40.54 regardless of the joint involved. M08.2A cannot be used for that subtype.

07Is a 7th character required for M08.2A?

No. M08.2A is a 6-character code and is complete as written. The M08 category does not use 7th-character extensions. The final character 'A' in this code is part of the site designation, not a 7th-character encounter indicator.

Sources & references

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

Mira AI Scribe

Mira AI Scribe captures the patient's age at symptom onset, the specific joint affected (e.g., temporomandibular, sternoclavicular), documented systemic features (fever pattern, rash, organomegaly), any associated IBD diagnosis, and imaging findings at the named site. Capturing the exact joint name prevents a downcode to M08.29 (unspecified site), which triggers payer scrutiny and may result in claim denial for specificity.

See how Mira captures M08.2A documentation