Thomas Greig, MD, MPH, MSIST
Thomas Greig, MD, MPH, MSIST is an Aerospace Medicine Physician in Oakton, VA, registered under NPI 1104788017. This provider registers 4 separate taxonomy codes, which usually means they practise across more than one recognised specialty. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 11711 LARIAT LN, Oakton, VA 22124. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| 037222 | GA | Aerospace Medicine Physician primary |
| 037222 | GA | Clinical Informatics Physician |
| 037222 | GA | Preventive Medicine/Occupational… |
| 037222 | GA | Occupational Medicine Physician |
This provider holds licence 037222 issued in GA. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
What Aerospace Medicine covers
Aerospace medicine focuses on the clinical care, research, and operational support of the health, safety, and performance of crewmembers and passengers of air and space vehicles, together with the support personnel who assist operation of such vehicles. This population often works and lives in remote, isolated, extreme, or enclosed environments under conditions of physical and psychological stress. Practitioners strive for an optimal human-machine match in occupational settings rich with environmental hazards and engineering countermeasures. NUCC Health Care Provider Taxonomy, code 2083A0100X
All registered taxonomy codes
This provider registers 4 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 2083A0100X | Aerospace Medicine Physician Aerospace Medicine | 037222 | GA | primary |
| 2083C0008X | Clinical Informatics Physician Clinical Informatics | 037222 | GA | |
| 2083P0500X | Preventive Medicine/Occupational Environmental Medicine Physician Preventive Medicine/Occupational Environmental Medicine | 037222 | GA | |
| 2083X0100X | Occupational Medicine Physician Occupational Medicine | 037222 | GA |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1104788017 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Nov 29, 2025 |
| Last updated | Nov 29, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | MD, MPH, MSIST |
| Practice address |
11711 LARIAT LN Oakton, VA 22124 (571) 265-9340 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 1 | 0 | 4 | 7 | 8 | 8 | 0 | 1 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 1 | 0 | 4 | 5 | 8 | 7 | 0 | 2 |
Sum = 53 · next multiple of 10 = 60 · check digit = 7 · actual last digit = 7
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.