CPT code 42100: Palate biopsy, tissue sampling2026 Medicare rate & RVUs in Guam
Report this service when a clinician takes a tissue sample from the roof of the mouth for evaluation of a suspicious oral lesion.
Medicare pays $161.08 for 42100 in the office in Guam (Hawaii, Guam, HI). 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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On this page 9 sections
What 42100 covers
This service covers taking a tissue sample from the palate, the roof of the mouth, for diagnostic examination. Otolaryngologists and oral and maxillofacial surgeons commonly perform it in an office, procedure room, or operating room when assessing a suspicious ulcer, patch, or mass. The work is sampling tissue for diagnosis, rather than removing a palate lesion as definitive treatment.
Select the code when the documented service is a palatal biopsy; record the sampled site, the finding or concern prompting the procedure, and the tissue submitted. CMS assigns a 10-day minor-procedure global period, so related postoperative visits during that interval are included. If multiple procedures subject to the standard reduction are performed in the same session, the highest-valued procedure is paid in full and the others at 50%. Palatal anatomy makes modifier 50 inappropriate. Medicare does not pay an assistant at surgery, and co-surgeon and team-surgery billing 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.
42100 in Hawaii, Guam, HI
| Payment locality | Office | Facility |
|---|---|---|
| Hawaii, Guam, HI | $161.08 | $106.01 |
How the 42100 rate is calculated
Each of 42100’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 · 42100
RVUs × geographic indexes × conversion factor
Work1.33
1.33 RVUs× 1.000 GPCI
Practice expense2.98
2.98 RVUs× 1.000 GPCI
Malpractice0.18
0.18 RVUs× 1.000 GPCI
Adjusted RVUs
4.4900
Conversion factor
$33.4009
Medicare rate
$149.97
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 42100
42100 has a 10-day global period: related visits in that window are included in the surgery payment.
CMS payment indicators · 42100
Palate biopsy, tissue sampling
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 010 | Minor procedure: the day of the procedure plus 10 days after are included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| 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. |
| Split (54/55/56) | 0.10/0.80/0.10 | Share of the payment for pre-op, the procedure itself, and post-op care. |
Global surgery period · 42100
Palate biopsy, tissue sampling
10-day global period ends
Oct 11, 2026
Covers Oct 1, 2026 through Oct 11, 2026 (11 days).
Visit on Oct 31, 2026
After the global period ends: visits and procedures are billed normally.
What modifiers do to the payment
Modifier 51 · payment effect
With and without the modifier
42100 without 51 · national office
$149.97
Palate biopsy, tissue sampling
42100-51 · Second procedure: 50%
$74.99
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%).
42100 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 42104Palatal excisionWithout closure
- 42100 describes diagnostic tissue sampling. 42104 is for excision of a palate lesion 1 cm or less.
- 42106Palate excisionSimple primary closure
- 42100 describes diagnostic tissue sampling. 42106 is for excision of a palate lesion over 1 cm.
- 42107Palatal lesion excisionWith complex repair
- 42100 describes diagnostic tissue sampling. 42107 is for extensive excision of a palate lesion.
42100 billing questions
When should this code be chosen instead of a palate excision code?
Use this code when the service is tissue sampling for diagnosis. When the procedure removes a palate lesion, consider the applicable excision code instead.
Can modifier 50 be reported for biopsies on both sides of the palate?
No. CMS identifies bilateral adjustment as inappropriate for this code because of the descriptor or anatomy.
Are related postoperative visits separately reported during the global period?
Related postoperative visits during the 10-day global period are included in the procedure.
What documentation supports reporting a palatal biopsy?
Document the palate site sampled, the clinical finding or concern that prompted sampling, and that tissue was obtained for diagnostic evaluation.
Can an assistant surgeon or co-surgeon be billed?
Medicare does not pay an assistant at surgery for this service, and co-surgeon and team-surgery billing are not permitted.
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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