Mark Brennan, DO
Mark Brennan, DO is a Vascular Surgery Physician in Johnson City, NY, registered under NPI 1174523443. 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 30 HARRISON ST STE 455, Johnson City, NY 13790. 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 |
|---|---|---|
| 217717 | NY | Vascular Surgery Physician primary |
| 217717 | NY | Surgery Physician |
This provider holds licence 217717 issued in NY. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
- Status
- Approved
- Provider type
- Practitioner - Vascular Surgery
- PAC ID
- 3779624549
- Enrollment ID
- I20091231000194
Medicare enrolment is recorded as approved under the provider type Practitioner - Vascular Surgery. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
What Vascular Surgery covers
A surgeon with expertise in the management of surgical disorders of the blood vessels, excluding the intracranial vessels or the heart. NUCC Health Care Provider Taxonomy, code 2086S0129X
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 | |
|---|---|---|---|---|
| 2086S0129X | Vascular Surgery Physician Vascular Surgery | 217717 | NY | primary |
| 208600000X | Surgery Physician | 217717 | NY |
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 | 1174523443 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jul 28, 2005 |
| Last updated | Sep 15, 2014 |
| Status | Active |
| Sole proprietor | No |
| Credential | DO |
| Practice address |
30 HARRISON ST STE 455 Johnson City, NY 13790 (607) 763-8100 Fax (607) 763-8048 |
| Mailing address |
346 GRAND AVE UNITED MEDICAL ASSOCIATES, PC Johnson City, NY 13790 |
| Other identifiers |
02082319
· Medicaid (NY) |
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 | 7 | 4 | 5 | 2 | 3 | 4 | 4 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 1 | 5 | 4 | 1 | 2 | 6 | 4 | 8 |
Sum = 57 · next multiple of 10 = 60 · check digit = 3 · actual last digit = 3
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.