Felix Tsai, M.D.
Felix Tsai, M.D. is a Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician in Louisville, KY, registered under NPI 1972703015. 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 411 E CHESTNUT ST, Louisville, KY 40202. 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 |
|---|---|---|
| 61904 | KY | Thoracic Surgery (Cardiothoracic Vascular… primary |
| N1191 | TX | Pediatric Cardiology Physician |
| 0101249419 | VA | Thoracic Surgery (Cardiothoracic Vascular… |
| N1191 | TX | Thoracic Surgery (Cardiothoracic Vascular… |
| FTL 41883 | TX | Thoracic Surgery (Cardiothoracic Vascular… |
| 27000 | SC | Thoracic Surgery (Cardiothoracic Vascular… |
Licences are recorded in 4 states: KY, TX, VA, SC. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
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.
Licensed in 4 states
This provider holds licences in 4 states: Kentucky, South Carolina, Texas and Virginia. The practice address on file is in Louisville, KY, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.
- Licence
- 61904
- Specialty
- Thoracic Surgery (Cardiothoracic…
- Licence
- 27000
- Specialty
- Thoracic Surgery (Cardiothoracic…
Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.
What Thoracic Surgery (Cardiothoracic Vascular Surgery) covers
A thoracic surgeon provides the operative, perioperative and critical care of patients with pathologic conditions within the chest. Included is the surgical care of coronary artery disease, cancers of the lung, esophagus and chest wall, abnormalities of the trachea, abnormalities of the great vessels and heart valves, congenital anomalies, tumors of the mediastinum and diseases of the diaphragm. The management of the airway and injuries of the chest is within the scope of the specialty. NUCC Health Care Provider Taxonomy, code 208G00000X
All registered taxonomy codes
This provider registers 6 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 208G00000X | Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician | 61904 | KY | primary |
| 2080P0202X | Pediatric Cardiology Physician Pediatric Cardiology | N1191 | TX | |
| 208G00000X | Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician | 0101249419 | VA | |
| 208G00000X | Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician | N1191 | TX | |
| 208G00000X | Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician | FTL 41883 | TX | |
| 208G00000X | Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician | 27000 | SC |
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 | 1972703015 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jul 18, 2007 |
| Last updated | Mar 26, 2026 |
| Status | Active |
| Sole proprietor | No |
| Credential | M.D. |
| Practice address |
411 E CHESTNUT ST Louisville, KY 40202 (502) 588-7641 Fax (502) 588-7700 |
| Mailing address |
PO BOX 776879 Chicago, IL 60677 |
| Other identifiers |
189048504
· CSHCN (TX) 8A4325 · BCBS (TX) 5917693 (NC) 1972703015 (VA) 189048503 (TX) 189048501 (TX) 189048502 · CSHCN (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 | 9 | 7 | 2 | 7 | 0 | 3 | 0 | 1 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 9 | 5 | 2 | 5 | 0 | 6 | 0 | 2 |
Sum = 55 · next multiple of 10 = 60 · 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.