Robert Nathanson, M.D.
Robert Nathanson, M.D. is a Hospitalist Physician in San Antonio, TX, registered under NPI 1316267875. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
The practice address on file is 4502 MEDICAL DR, San Antonio, TX 78229. 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 |
|---|---|---|
| P5558 | TX | Hospitalist Physician primary |
| P5558 | TX | Internal Medicine Physician |
This provider holds licence P5558 issued in TX. 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 Hospitalist covers
Hospitalists are physicians whose primary professional focus is the general medical care of hospitalized patients. Their activities include patient care, teaching, research, and leadership related to Hospital Medicine. The term 'hospitalist' refers to physicians whose practice emphasizes providing care for hospitalized patients. NUCC Health Care Provider Taxonomy, code 208M00000X
All registered taxonomy codes
This provider registers 2 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 208M00000X | Hospitalist Physician | P5558 | TX | primary |
| 207R00000X | Internal Medicine Physician | P5558 | TX |
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 | 1316267875 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jun 8, 2010 |
| Last updated | Jun 3, 2026 |
| Status | Active |
| Sole proprietor | No |
| Credential | M.D. |
| Practice address |
4502 MEDICAL DR San Antonio, TX 78229 (210) 358-4000 |
| Mailing address |
7703 FLOYD CURL DR San Antonio, TX 78229 |
| Other identifiers |
324378401
· Medicaid (TX) 324378402 · Other (TX) |
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 | 3 | 1 | 6 | 2 | 6 | 7 | 8 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 3 | 2 | 6 | 4 | 6 | 5 | 8 | 5 |
Sum = 65 · next multiple of 10 = 70 · check digit = 5 · actual last digit = 5
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.