Monitoring of interstitial fluid pressure within a muscle compartment, including device insertion (wick catheter or needle manometer technique), performed to detect compartment syndrome.

Verified May 8, 2026 · 6 sources ↓

Medicare: $278.23
Total RVUs: 8.33
Global, days: 0
Region: General

Drawn from CMSAAPC

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 6 cited references ↓

Specify the extremity and compartment(s) measured (e.g., anterior compartment, right lower leg)
Record the technique used: wick catheter or needle manometer
Document the pressure readings obtained and the clinical interpretation
State the clinical indication — compartment syndrome suspected versus routine post-op monitoring
Note each separate session if the procedure was repeated, with the time of each session
Identify the physician performing each session if repeat billing involves a different provider

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 50 Bilateral procedure 51 Multiple procedures 52 Reduced services 59 Distinct service 76 Repeat, same physician 77 Repeat, another physician 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 20950 covers the measurement of interstitial fluid pressure inside a muscle compartment, including the insertion of the measuring device — whether a wick catheter or needle manometer. The procedure is used to confirm or rule out compartment syndrome, a time-critical condition where elevated intracompartmental pressure compresses vasculature and nerves, threatening permanent tissue damage. The 000-day global period means no bundled pre- or post-op services are included; each session stands alone.

Bill 20950 per extremity, per session — not per compartment. If the surgeon measures anterior and posterior compartments of the same leg, that is one unit. Bilateral legs on the same day: report 20950-LT and 20950-RT as two line items. If the same physician repeats the study later that day (e.g., for exercise-induced compartment syndrome), append modifier 76 to the second claim.

A critical NCCI restriction: when a procedure routinely carries risk of anterior compartment compression — such as distal lower extremity surgery — 20950 cannot be billed separately for post-op monitoring performed as a standard precaution. Separate billing is defensible only when the pressure monitoring is a distinct clinical service, not routine surveillance bundled into the operative episode. Document the clinical indication clearly to survive audit.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	1.23
Practice expense RVU	6.88
Malpractice RVU	0.22
Total RVU	8.33
Medicare national rate	$278.23
Global period	0 days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$278.23
HOPD (APC 5071) Hospital outpatient department	$723.47
ASC (PI G2) Ambulatory surgical center (freestanding)	$388.55

Common denial reasons

The recurring reasons claims for CPT 20950 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Billed per compartment rather than per extremity — exceeds expected units
Unbundled from a same-day surgical procedure where post-op pressure monitoring is considered routine (NCCI restriction for distal lower extremity procedures)
Missing laterality modifier when bilateral studies were performed — payer cannot adjudicate two units without LT/RT
Repeat same-day session submitted without modifier 76 (same physician) or 77 (different physician), triggering duplicate claim edit
Insufficient documentation of clinical indication distinguishing a standalone diagnostic service from routine post-operative monitoring

Frequently asked questions

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

01Can I bill 20950 twice if the surgeon tested both the anterior and posterior compartments of the same leg?

No. Bill one unit of 20950 per extremity per session, regardless of how many compartments were tested in that limb.

02How do I bill when compartment pressures are measured in both legs during the same session?

Report 20950-LT and 20950-RT as two separate line items. Do not use modifier 50 (bilateral) for this code — payers expect individual laterality modifiers, not a single bilateral unit.

03The surgeon repeated compartment pressure measurements later the same day for exercise-induced compartment syndrome. How do I code the second session?

Report a second unit of 20950 for the later session and append modifier 76 if the same physician repeated it, or modifier 77 if a different physician performed the repeat.

04Can 20950 be billed after distal lower extremity surgery as part of post-op monitoring?

No. CMS NCCI policy explicitly prohibits separate reporting of 20950 when interstitial fluid pressure monitoring is a routine part of post-op care for procedures that carry anterior compartment compression risk, such as distal lower extremity surgeries.

05What ICD-10 diagnosis codes support a standalone 20950 claim?

Acute compartment syndrome codes (M79.A-series by site) are the primary supporting diagnoses. Suspected compartment syndrome following trauma or surgery should be coded with the appropriate injury or post-procedural complication code. Payers will scrutinize a 20950 claim paired only with the underlying injury code and no compartment syndrome diagnosis.

06Does 20950 have a global period that would prevent same-day E&M billing?

The global period is 000 days — the day of the procedure only. A separately identifiable E&M service on the same date requires modifier 25 appended to the E&M code. Because 20950 is a minor procedure, the decision to perform it is generally bundled into any E&M on the same day unless that visit addressed a separate problem.

Sources & references

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

01CMS Physician Fee Schedule 2026
02CMS NCCI Medicare Coding Policy Manual, Chapter 4 (CPT Codes 20000-29999), Revision Date 1/1/2022 — https://www.cms.gov/files/document/chapter4cptcodes20000-29999final11.pdf
03CMS NCCI Medicare Policy Manual Complete PDF, Revision Date 1/1/2025 — https://www.cms.gov/files/document/2025nccimedicarepolicymanualcompletepdf.pdf
04AAPC Orthopedic Coding Alert: Report 20950 per Extremity (Apr 21, 2008) — https://www.aapc.com/codes/coding-newsletters/my-orthopedic-coding-alert/reader-questions-report-20950-per-extremity-article
05AAPC Forum: CPT 20950 Modifier Discussion — https://www.aapc.com/discuss/threads/cpt-20950.23803/
06AAPC Codify CPT 20950 — https://www.aapc.com/codes/cpt-codes/20950

Mira AI Scribe

Mira's AI scribe captures the compartment(s) tested, technique used (wick catheter or needle manometer), pressure values recorded, laterality, time of each session, and the specific clinical indication prompting the study. That detail prevents the two most common denial triggers: unbundling edits tied to routine post-op monitoring and unit rejections from missing laterality or repeat-session modifiers.

See how Mira captures CPT 20950 documentation