Gregory P. Kooyman, P.A.
Physician Assistant · Dayton, OH
Gregory P. Kooyman, P.A. is a physician assistant with a practice address in Dayton, Ohio, and NPI 1346334406, issued on Oct 3, 2006. Check the license (Ohio 50-000356, as entered in NPPES) with the Ohio board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Gregory P. Kooyman
- Credential
- P.A.
- Primary taxonomy
- Physician Assistant 363A00000X
- License number
- 50-000356 OH
Self-reported in NPPES; status is on the state search - Practice location
- 1 Wyoming St, Dayton, OH 45409
- Phone
- (513) 281-4400
- Enumerated
- Oct 3, 2006
- Record last updated
- May 21, 2013 (not updated in 13 years: call before relying on the address or phone)
- Fax
- (513) 587-8213
- Entity
- Type 1 · individual
8 nearest physician assistant records → All 5,325 in Ohio → Look up another NPI →
Also registered at 1 Wyoming St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Gregory P. Kooyman in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich Ohio board licenses this profession
Search for license 50-000356Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
98% fewer Medicare Part D claims than the average physician assistant in 2024
15 Medicare Part D claims for 15 beneficiaries, against an average of 830 among the 101,058 providers of this specialty who prescribed in Part D.
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.
Gregory P. Kooyman among 5,325 physician assistant records in Ohio
Gregory P. Kooyman, P.A. is one of 5,325 physician assistant records with a practice address in Ohio. 80% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 2% of them.
- NPI issued2006 · 2% of these records are older, 87% newer
- In a Medicare fileYes · 80% of these records are
- In the CMS Doctors and Clinicians fileNo · 68% of these records are
- Record last updated2013 · 37% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363A00000X and a Ohio practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
250 physician assistant records list a practice address in Dayton
They are 250 of the 12,431 NPPES records with a practice address in Dayton, and 5,325 physician assistant records in Ohio.
All 5,325 in Ohio → Every provider in Dayton → Physician Assistant nationwide →
The 8 physician assistant records with the nearest ZIP codes
- Pramila Bharwani, PA-CDayton, OH 454091841295086
- Edward Chance, P.A.Dayton, OH 454091710071840
- Lisa Grow, PACDayton, OH 454091134217011
- Sean Haig, PADayton, OH 454091881760270
- Kelli Huesman, PADayton, OH 454091700817483
- Angela Kemp, PADayton, OH 454091366779266
- Katherine Mattingly, PA-CDayton, OH 454091699774174
- Mildred Roach, P.A.Dayton, OH 454091215021415
Common questions
What is Gregory P. Kooyman, P.A.'s NPI number?
Gregory P. Kooyman, P.A.'s National Provider Identifier (NPI) is 1346334406, issued on Oct 3, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Gregory P. Kooyman, P.A. located?
The NPPES record lists a practice address at 1 Wyoming St, Dayton, OH, 45409. Phone: (513) 281-4400. Providers update this record themselves, so call before visiting.
How can I verify Gregory P. Kooyman, P.A.'s license?
NPPES lists Ohio license number 50-000356, as entered by the provider. Search the Ohio board that licenses this profession; the NPPES record confirms identity only.
How much does Gregory P. Kooyman, P.A. prescribe under Medicare Part D?
In 2024, Gregory P. Kooyman, P.A. had 15 Medicare Part D claims for 15 beneficiaries; the average among physician assistant prescribers was 830. Part D covers Medicare prescriptions only.
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.