CPT code 61001: Subdural aspiration2026 Medicare rate & RVUs in Guam
Report this service for needle access to the cranial subdural space to aspirate a fluid collection or deliver medication into that space.
CMS doesn’t publish an office rate for 61001 in Guam.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
On this page 9 sections
What 61001 covers
A neurosurgeon or other qualified physician uses a needle to enter the cranial subdural space, most often to remove fluid from a subdural collection such as an effusion or hygroma. The code also encompasses medication delivery through this subdural puncture. It is distinct from withdrawing fluid from a ventricular cavity, a cistern, or a shunt reservoir; the documented access site determines the appropriate code.
Report the service when the procedure record supports subdural-space access and aspiration or medication delivery. Document the clinical indication, the space entered, the side or sides treated, and what was aspirated or injected. CMS assigns a 0-day global period, so same-day preoperative and postoperative care is included. The code is priced as bilateral; modifier 50 does not increase payment. When other procedures are performed in the same session, the highest-valued procedure is paid in full and other procedures are subject to the standard 50% multiple-procedure reduction. Medicare does not pay an assistant at surgery for this code; co-surgeons and team surgery are not permitted.
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.
61001 in Hawaii, Guam
| Payment locality | Office | Facility |
|---|---|---|
| Hawaii, Guam | Unavailable | $102.57 |
How the 61001 rate is calculated
Each of 61001’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 · 61001
RVUs × geographic indexes × conversion factor
Work1.45
1.45 RVUs× 1.000 GPCI
Practice expense1.12
1.12 RVUs× 1.000 GPCI
Malpractice0.60
0.60 RVUs× 1.000 GPCI
Adjusted RVUs
3.1700
Conversion factor
$33.4009
Medicare rate
$105.88
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 61001
The CMS indicators that decide how 61001 is paid alongside other services.
CMS payment indicators · 61001
Subdural aspiration
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 000 | Same-day global: pre- and post-op care on the day of the procedure is included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 2 | Already bilateral by definition: paid once at 100%. |
| 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. |
What modifiers do to the payment
Modifier 51 · payment effect
With and without the modifier
61001 without 51 · national facility
$105.88
Subdural aspiration
61001-51 · Second procedure: 50%
$52.94
When this isn’t the highest-valued procedure in the session, Medicare pays 50% of its fee schedule amount (the highest is paid at 100%).
61001 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 61000Subdural tap
- Choose 61001 for cranial subdural-space access; choose 61000 when the physician punctures a ventricular cavity.
- 61050Cisternal puncture
- 61050 addresses access through a cisternal puncture. Use 61001 when the documented target is the cranial subdural space.
- 61070Shunt access
- 61070 involves puncturing shunt tubing or its reservoir. This code describes direct puncture of the cranial subdural space.
61001 billing questions
How is this code different from 61000?
This code is for puncture of the cranial subdural space. Code 61000 is used when the target is a ventricular cavity.
Should modifier 50 be added for bilateral treatment?
CMS prices this code as bilateral, and modifier 50 does not increase payment. Document which side or sides were treated.
What same-day care is included?
The code has a 0-day global period, so same-day preoperative and postoperative care is included in the procedure.
Can an assistant surgeon or co-surgeon be reported?
Medicare does not pay an assistant at surgery for this code. Co-surgeons and team surgery are not permitted.
How does the multiple-procedure rule affect payment?
For procedures performed in the same session, the highest-valued procedure is paid in full and the other procedures are paid at 50%.
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
Show the CMS file lines behind this rate
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