William J. Mast, FNP-C
Family Nurse Practitioner · Greenville, TX
William J. Mast, FNP-C is a family nurse practitioner with a practice address in Greenville, Texas, and NPI 1659089811, issued on Nov 7, 2022. Check the license (Texas 1098502, as entered in NPPES) with the Texas board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- William J. Mast
- Credential
- FNP-C
- Primary taxonomy
- Family Nurse Practitioner 363LF0000X
- License number
- 1098502 TX
Self-reported in NPPES; status is on the state search - Practice location
- 3900 Joe Ramsey Blvd E Ste 6, Greenville, TX 75401
- Phone
- (903) 455-1100
- Enumerated
- Nov 7, 2022
- Record last updated
- Dec 8, 2025
- Fax
- (903) 455-1114
- Medicare enrollment
- Enrolled (PECOS I20221203000591); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest family nurse practitioner records → All 21,242 in Texas → Look up another NPI →
Also registered at 3900 Joe Ramsey Blvd E Ste 6
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Maddison Davis, FNP-CFamily Nurse Practitioner1912598772
Verify William J. Mast in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich Texas board licenses this profession
Search for license 1098502Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
32% more Medicare Part D claims than the average family nurse practitioner in 2024
1,722 Medicare Part D claims for 746 beneficiaries, against an average of 1,305 among the 140,557 providers of this specialty who prescribed in Part D. Brand-name drugs were 7% of claims.
Most prescribed
- Ketoconazole312 claims
- Triamcinolone Acetonide254 claims
- Doxycycline Hyclate167 claims
- Clobetasol Propionate151 claims
- Fluorouracil120 claims
- Mupirocin91 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
The practice group's MIPS final score for 2023 (Medicare payment program): 82 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $4,510.46
142 payments; by number, the most common kind was food and beverage; the largest payer was E.R. Squibb & Sons, L.L.C. The 99,489 providers of this specialty with any payment received $650.95 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Matthew D Barrows MD PAGreenville, TX
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
William J. Mast among 21,242 family nurse practitioner records in Texas
William J. Mast, FNP-C is one of 21,242 family nurse practitioner records with a practice address in Texas. 75% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2022, is newer than 74% of them.
- NPI issued2022 · 74% of these records are older, 20% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileYes · 53% of these records are
- Graduated2022 · median 2018 among the 11,286 with a school on file
- Record last updated2025 · 38% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363LF0000X and a Texas practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
50 family nurse practitioner records list a practice address in Greenville
They are 50 of the 586 NPPES records with a practice address in Greenville, and 21,242 family nurse practitioner records in Texas.
All 21,242 in Texas → Every provider in Greenville → Family Nurse Practitioner nationwide →
The 8 family nurse practitioner records with the nearest ZIP codes
- Ginger Brooks, APRNGreenville, TX 754011881998078
- Laney Bullock, FNP-CGreenville, TX 754011528432655
- Donna Callicoat, NPGreenville, TX 754011396990628
- William Crowe, RN, FNPGreenville, TX 754011023014180
- Patrick Hill, FNPGreenville, TX 754011013024033
- Michelle Karlin, RN AOCNP FNP -BCGreenville, TX 754011528020310
- Brucealynea Knowlton, FNPGreenville, TX 754011366776411
- Michelle Mersmann, FNP-BCGreenville, TX 754011912391103
Common questions
What is William J. Mast, FNP-C's NPI number?
William J. Mast, FNP-C's National Provider Identifier (NPI) is 1659089811, issued on Nov 7, 2022. An NPI identifies a provider in billing; it is not a license.
Where is William J. Mast, FNP-C located?
The NPPES record lists a practice address at 3900 Joe Ramsey Blvd E Ste 6, Greenville, TX, 75401. Phone: (903) 455-1100. Providers update this record themselves, so call before visiting.
How can I verify William J. Mast, FNP-C's license?
NPPES lists Texas license number 1098502, as entered by the provider. Search the Texas board that licenses this profession; the NPPES record confirms identity only.
How much does William J. Mast, FNP-C prescribe under Medicare Part D?
In 2024, William J. Mast, FNP-C had 1,722 Medicare Part D claims for 746 beneficiaries; the average among family nurse practitioner prescribers was 1,305. Part D covers Medicare prescriptions only.
What is William J. Mast, FNP-C's MIPS final score?
The 2023 MIPS final score is 82 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.