Gregor Siebert, P.A.
NPI 1700873510 · Medical Physician Assistant · Alexandria, VA
Enrolled with Medicare as Practitioner - Physician Assistant · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Gregor Siebert, P.A. is a Medical Physician Assistant provider in Alexandria, VA (NPI 1700873510).
Provider details
- NPI number
- 1700873510
- Entity type
- Individual
- Primary specialty
- Medical Physician AssistantPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- P.A.
- Sex
- Male
- Sole proprietor
- No
- License
- 0110004442 (VA)
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 tenure28% of score
20 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
52 Medicare services, 2024 (ranked within specialty)
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 methodology.
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) |
|---|---|---|
| New Patient Office Or Other Outpatient Visit With Low Level of Medical Decision Making, If Using Time, 30 Minutes Or More99203 | 22 | $105 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 17 | $86 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 13 | $119 |
Typical Medicare-allowed amounts for these services range $86–$119 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
Practice location
Mailing address
Registry dates
- Enumerated
- 2005-10-06
- Last updated
- 2022-02-02
- Certified
- 2022-02-02
Frequently asked questions
- What is Gregor Siebert's NPI number?
- Gregor Siebert's National Provider Identifier (NPI) is 1700873510, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Gregor Siebert's specialty?
- Gregor Siebert is listed in the NPPES registry with a primary specialty of Medical Physician Assistant (Physician Assistants & Advanced Practice Nursing Providers).
- Where is Gregor Siebert located?
- Gregor Siebert's practice location on file with NPPES is 6311 Richmond Hwy, Alexandria, VA 22306-6410.
- What is Gregor Siebert's phone number?
- The practice phone number listed in the NPPES registry for Gregor Siebert is (703) 647-6087.
- Does Gregor Siebert accept Medicare?
- Gregor Siebert is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Gregor Siebert's NPI active?
- Yes — Gregor Siebert's NPI (1700873510) is active in the NPPES registry as of the last update on 2022-02-02.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.