William Mast, FNP-C
NPI 1659089811 · Family Nurse Practitioner · Greenville, TX
Enrolled with Medicare as Practitioner - Nurse Practitioner · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Mast, FNP-C is a Family Nurse Practitioner provider in Greenville, TX (NPI 1659089811).
Provider details
- NPI number
- 1659089811
- Entity type
- Individual
- Primary specialty
- Family Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- FNP-C
- Sex
- Male
- Sole proprietor
- No
- License
- 1098502 (TX)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
3 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
7,685 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Destruction of Precancer Skin Growth, 2-14 Growths17003 | 2,557 | $5 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 1,064 | $73 |
| Destruction of Precancer Skin Growth, 1 Growth17000 | 1,013 | $40 |
| Destruction of Skin Growth, 1-14 Growths17110 | 735 | $90 |
| Biopsy of Related Skin Growth, First Growth11102 | 681 | $68 |
| Established Patient Office Or Other Outpatient Visit With Straightforward Medical Decision Making, If Using Time, 10 Minutes Or More |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 24 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Ketoconazole | 312 | 140 |
| Triamcinolone Acetonide | 254 | 213 |
| Doxycycline Hyclate | 167 | 91 |
| Clobetasol Propionate | 151 | 106 |
| Fluorouracil | 120 | 110 |
| Mupirocin | 91 | 81 |
| Clindamycin Phosphate | 65 | 42 |
| Hydrocortisone | 63 | 60 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$4,510 across 142 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2022-11-07
- Last updated
- 2025-12-08
- Certified
- 2025-12-08
Frequently asked questions
- What is William Mast's NPI number?
- William Mast's National Provider Identifier (NPI) is 1659089811, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Mast's specialty?
- William Mast is listed in the NPPES registry with a primary specialty of Family Nurse Practitioner (Physician Assistants & Advanced Practice Nursing Providers).
- Where is William Mast located?
- William Mast's practice location on file with NPPES is 3900 Joe Ramsey Blvd E Ste 6, Greenville, TX 75401-7705.
- What is William Mast's phone number?
- The practice phone number listed in the NPPES registry for William Mast is (903) 455-1100.
- Does William Mast accept Medicare?
- William Mast is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Mast's NPI active?
- Yes — William Mast's NPI (1659089811) is active in the NPPES registry as of the last update on 2025-12-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.