ICD-10-CM · Elbow

M70.20

Inflammation of the olecranon bursa at the tip of the elbow, coded when the operative or clinical note does not specify right or left side.

Verified May 8, 2026 · 7 sources ↓

Status: Billable
Chapter: 13
Related CPT: 5
Region: Elbow

Drawn from CDCICD10DataAAPCIcdcodesCMS

Documentation tips

What should appear in the chart to support M70.20.

Source · Editorial brief grounded in 7 cited references ↓

Document laterality explicitly — 'right elbow' or 'left elbow' — to avoid defaulting to the unspecified M70.20 and losing coding specificity.
Record the clinical basis for non-infective bursitis: onset mechanism (pressure, trauma, occupational use), duration, and any imaging findings (X-ray, ultrasound, MRI showing bursal distension).
If the condition is occupation- or activity-related, document the causative activity so an external cause code from Y93.- can be appended per the M70 category instruction.
Note whether bursal fluid aspiration was performed and include fluid analysis results — if WBC and culture indicate infection, the diagnosis must shift to M71.12- rather than M70.2-.
Document any prior conservative care (compression, NSAIDs, aspiration, corticosteroid injection) to support medical necessity for surgical intervention such as bursectomy (CPT 24105).

Related CPT procedures

Procedure codes commonly billed with M70.20. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

20605 $57.12

Aspiration and/or injection of an intermediate joint or bursa — such as the wrist, elbow, ankle, acromioclavicular joint, or olecranon bursa — performed without ultrasound guidance.

20606 $94.19

Aspiration and/or injection of an intermediate joint or bursa — such as the wrist, elbow, ankle, acromioclavicular, temporomandibular, or olecranon bursa — performed with real-time ultrasound guidance and permanent image recording and reporting.

24105 $358.06

Surgical removal of the olecranon bursa at the posterior elbow, performed as a complete excision rather than drainage or aspiration.

73070 $29.39

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

73080 $33.07

Radiologic examination of the elbow, complete, requiring a minimum of three views.

Common coding pitfalls

The recurring mistakes coders make with M70.20 and adjacent codes.

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

Assigning M70.20 when laterality is clearly stated in the note — providers frequently document 'left' or 'right' but coders default to the unspecified code, which downcodes specificity and can trigger payer edits.
Using M70.20 for septic olecranon bursitis — infected bursal fluid with positive culture maps to M71.12- (infective bursitis), not M70.2-; the wrong code causes incorrect DRG assignment.
Omitting the Y93.- activity external cause code when the record documents an occupational or recreational cause, violating the M70 category 'Use additional code' instruction.
Confusing M70.20 with M70.30 (Other bursitis of elbow, unspecified) — M70.30 is for non-olecranon elbow bursae; confirm the anatomical site before selecting between these adjacent codes.
Applying M70.20 when documentation only states 'bursitis NOS' without specifying olecranon — that maps to M71.9-, not M70.20, per the Excludes1 note at M70.

Clinical context

Source · Editorial summary grounded in 7 cited references ↓

M70.20 applies to non-infective olecranon bursitis when the affected elbow is not documented as right or left. The olecranon bursa sits between the skin and the olecranon process; inflammation arises from repetitive pressure, direct trauma, or occupational overuse. This code lives under category M70, which covers soft tissue disorders of occupational origin — meaning the category includes an instruction to add an external cause activity code (Y93.-) when the condition is work- or activity-related.

Laterality drives code selection within M70.2: M70.21 for right elbow, M70.22 for left elbow, M70.20 only when the side is genuinely undocumented. Use M70.20 as a temporary working code if laterality is pending clarification, but resolve it before final claim submission. Do not use M70.20 when the provider has documented a side — that constitutes undercoding and invites medical necessity scrutiny.

If infection is confirmed (e.g., septic bursitis from Staphylococcus aureus, positive bursal fluid culture), do not use M70.20. Route to M71.12- (Other infective bursitis, elbow) instead. The Excludes1 note at M70 also bars using M70.20 when the only documentation is 'bursitis NOS' — that maps to M71.9-. Bursitis of shoulder routes to M75.5, not M70.

Sibling codes

Other billable codes under M70.2 (laterality / anatomic variants).

M70.21

Olecranon bursitis, right elbow

M70.22

Olecranon bursitis, left elbow

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 7 cited references ↓

01When should I use M70.20 instead of M70.21 or M70.22?

Use M70.20 only when the provider's documentation genuinely does not specify which elbow is affected. If the note says 'right' or 'left,' use M70.21 or M70.22 respectively. M70.20 should rarely appear on a final claim from an orthopedic practice.

02Can I use M70.20 for septic or infected olecranon bursitis?

No. Infected olecranon bursitis — confirmed by positive culture, elevated bursal fluid WBC, or clinical signs of infection — routes to M71.12- (Other infective bursitis, elbow). Using M70.20 for septic bursitis causes incorrect DRG assignment and potential compliance exposure.

03Does M70.20 require an external cause code?

When the bursitis is related to a specific activity or occupational exposure, yes — append a Y93.- code per the M70 category instruction. If the etiology is idiopathic or undocumented, the external cause code is not required but document the absence of a known cause.

04What CPT codes are typically billed with M70.20?

Aspiration or injection of the olecranon bursa pairs with CPT 20605 (intermediate joint or bursa aspiration/injection, without ultrasound) or 20606 (with ultrasound guidance). Surgical bursectomy at the elbow uses CPT 24105. Elbow X-rays to evaluate osteophyte formation or rule out fracture use 73070 (two views) or 73080 (minimum three views).

05Is M70.20 valid for inpatient DRG assignment?

Yes. M70.20 groups to MS-DRG 557 (Tendonitis, myositis and bursitis with MCC) or 558 (without MCC) under MS-DRG v43.0. The MCC/CC status of comorbidities determines which DRG fires.

06What is the Excludes1 note I need to watch at the M70 category level?

M70 carries an Excludes1 for bursitis NOS (M71.9-). This means you cannot use M70.20 alongside M71.9- for the same elbow, and if documentation only supports 'bursitis NOS' without specifying olecranon, M71.9- is the correct code, not M70.20.

07Should I code M70.20 bilaterally if both elbows are affected?

No single code covers bilateral olecranon bursitis. Assign M70.21 for the right elbow and M70.22 for the left elbow as separate diagnosis codes. M70.20 does not substitute for bilateral documentation.

Sources & references

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

Mira AI Scribe

Mira captures the affected side, onset mechanism (pressure, trauma, or occupational repetition), duration of symptoms, bursal fluid analysis results if aspiration was performed, and any prior conservative treatment. Locking in laterality at the point of documentation prevents defaulting to the unspecified M70.20 and eliminates the need for a costly post-submission query.

See how Mira captures M70.20 documentation