Gregor Siebert, P.A.
Medical Physician Assistant · Alexandria, VA
Gregor Siebert, P.A. is a medical physician assistant with a practice address in Alexandria, Virginia, and NPI 1700873510, issued on Oct 6, 2005. Check the license (Virginia 0110004442, as entered in NPPES) with the Virginia board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Gregor Siebert
- Credential
- P.A.
- Primary taxonomy
- Medical Physician Assistant 363AM0700X
- License number
- 0110004442 VA
Self-reported in NPPES; status is on the state search - Practice location
- 6311 Richmond Hwy, Alexandria, VA 22306
- Phone
- (703) 647-6087
- Enumerated
- Oct 6, 2005
- Record last updated
- Feb 2, 2022
- Fax
- (703) 647-6088
- Medicare enrollment
- Enrolled (PECOS I20141222002696); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest medical physician assistant records → All 941 in Virginia → Look up another NPI →
Also registered at 6311 Richmond Hwy
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Benjamin Jessee, PA-CPhysician Assistant1730896242
Verify Gregor Siebert in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich Virginia board licenses this profession
Search for license 0110004442Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
97% fewer Medicare Part D claims than the average medical physician assistant in 2024
32 Medicare Part D claims for 17 beneficiaries, against an average of 1,148 among the 23,801 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.
The practice group's MIPS final score for 2023 (Medicare payment program): 62.1 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).
Bills Medicare through one group practice
- Patient First Richmond Medical Group PLLCAlexandria, VA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Gregor Siebert among 941 medical physician assistant records in Virginia
Gregor Siebert, P.A. is one of 941 medical physician assistant records with a practice address in Virginia. 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 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 96% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileYes · 56% of these records are
- Graduated2001 · median 2014 among the 525 with a school on file
- Record last updated2022 · 52% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363AM0700X and a Virginia practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Medical Physician Assistant providers in Virginia
There are 941 medical physician assistant records in Virginia.
All 941 in Virginia → Every provider in Alexandria → Medical Physician Assistant nationwide →
The 8 medical physician assistant records with the nearest ZIP codes
- William Bartow JrAlexandria, VA 223061023069531
- Leona Fontana, PAAlexandria, VA 223061669422408
- Christine Hollenbeck, PA-CAlexandria, VA 223061770821381
- Valerie Villegas, PAAlexandria, VA 223061518142660
- Caroline Babington, PA-CAlexandria, VA 223041306010111
- Kristen Dreyer, PA-CAlexandria, VA 223041316418544
- Prachi MadanAlexandria, VA 223041619357308
- Kathleen Ritchie, PA-CAlexandria, VA 223041871963173
Common questions
What is Gregor Siebert, P.A.'s NPI number?
Gregor Siebert, P.A.'s National Provider Identifier (NPI) is 1700873510, issued on Oct 6, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Gregor Siebert, P.A. located?
The NPPES record lists a practice address at 6311 Richmond Hwy, Alexandria, VA, 22306. Phone: (703) 647-6087. Providers update this record themselves, so call before visiting.
How can I verify Gregor Siebert, P.A.'s license?
NPPES lists Virginia license number 0110004442, as entered by the provider. Search the Virginia board that licenses this profession; the NPPES record confirms identity only.
How much does Gregor Siebert, P.A. prescribe under Medicare Part D?
In 2024, Gregor Siebert, P.A. had 32 Medicare Part D claims for 17 beneficiaries; the average among medical physician assistant prescribers was 1,148. Part D covers Medicare prescriptions only.
What is Gregor Siebert, P.A.'s MIPS final score?
The 2023 MIPS final score is 62.1 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.