CPT code 64643: Chemodenervation, additional extremity, 1-4 muscles2026 Medicare rate & RVUs in Texas
Reports chemodenervation of an additional extremity when treatment targets one to four muscles there, alongside the primary extremity procedure.
Medicare pays $94.60–$102.71 for 64643 in the office in Texas, from Beaumont, TX to Houston, TX. Which amount applies depends on the service address.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
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What 64643 covers
This add-on code represents chemodenervation of an additional limb, treating one to four muscles in that extremity. It is commonly used when a clinician injects botulinum toxin to manage focal spasticity, such as after stroke, traumatic brain injury, or in cerebral palsy. Physicians and other qualified practitioners typically perform the injections in an office or facility setting, selecting target muscles based on the patient’s functional goals and examination findings.
Report 64643 with the primary extremity chemodenervation service, generally 64642, when another extremity is treated at the same session. The muscle count is assessed separately for each extremity; this code represents an additional extremity with one to four treated muscles, not each individual muscle or injection site. Documentation should identify the treated extremity, muscles, indication, and administered treatment. CMS classifies this as an add-on code: it is billed only with a primary procedure, and its payment falls within that procedure’s global period.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 64643 pays more and less in Texas
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
8 payment localities
$94.60 to $102.71
8 of 8 payment localities
| Payment locality | Office | Facility |
|---|---|---|
| Austin, TX | $102.11 | $59.71 |
| Beaumont, TX | $94.60 | $58.13 |
| Brazoria, TX | $98.02 | $58.30 |
| Dallas, TX | $98.93 | $59.01 |
| Fort Worth, TX | $98.50 | $58.98 |
| Galveston, TX | $98.50 | $58.70 |
| Houston, TX | $102.71 | $62.91 |
| Rest of Texas | $96.45 | $58.41 |
How the 64643 rate is calculated
Each of 64643’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 64643
RVUs × geographic indexes × conversion factor
Work1.19
1.19 RVUs× 1.000 GPCI
Practice expense1.57
1.57 RVUs× 1.000 GPCI
Malpractice0.23
0.23 RVUs× 1.000 GPCI
Adjusted RVUs
2.9900
Conversion factor
$33.4009
Medicare rate
$99.87
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 64643
The CMS indicators that decide how 64643 is paid alongside other services.
CMS payment indicators · 64643
Chemodenervation, additional extremity, 1-4 muscles
| Rule | CMS value | What it means |
|---|---|---|
| Global period | ZZZ | Add-on code: falls within the primary procedure’s global period. |
| Multiple procedures | 0 | No multiple-procedure reduction. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 1 | Not paid (statutory restriction). |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
64643 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 64642ChemodenervationOne extremity, 1–4 muscles
- 64642 covers the primary extremity treated with one to four muscles. 64643 is for each additional extremity in that same muscle-count range.
- 64644Muscle chemodenervationOne extremity, five or more muscles
- 64644 applies to the primary extremity when five or more muscles are treated; 64643 is for an additional extremity with one to four muscles.
- 64645Muscle chemodenervationAdditional extremity, five-plus muscles
- Both codes describe an additional extremity, but 64645 is used when five or more muscles are treated there; 64643 is for one to four.
64643 billing questions
When is 64643 used instead of 64642?
64642 reports the primary extremity treated with one to four muscles. Use 64643 for each additional extremity treated with one to four muscles during the service.
Can 64643 be billed by itself?
No. It is an add-on code and must be reported with a primary procedure, generally 64642 for the first extremity.
Is the code counted per muscle or per extremity?
It is counted per additional extremity. The extremity must have one to four muscles treated; the code is not reported once for each muscle or injection site.
When should 64645 be used instead?
Use 64645 for an additional extremity when five or more muscles are treated there. The one-to-four muscle threshold is evaluated separately for each extremity.
What documentation supports 64643?
Document the additional extremity, the muscles treated in that limb, the indication for chemodenervation, and the treatment performed.
How does the global-period rule affect 64643?
CMS treats 64643 as an add-on service paid within the primary procedure’s global period. It must accompany a primary procedure.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
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