Stylianos Theofanidis, MD
Stylianos Theofanidis, MD is a Neonatal-Perinatal Medicine Physician in Greenwich, CT, registered under NPI 1912926908. 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 5 PERRYRIDGE ROAD GREENWICH HOSPITAL, Greenwich, CT 06830. 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 |
|---|---|---|
| 028038 | CT | Neonatal-Perinatal Medicine Physician primary |
| 028038 | CT | Pediatrics Physician |
This provider holds licence 028038 issued in CT. 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 Neonatal-Perinatal Medicine covers
A pediatrician who is the principal care provider for sick newborn infants. Clinical expertise is used for direct patient care and for consulting with obstetrical colleagues to plan for the care of mothers who have high-risk pregnancies. NUCC Health Care Provider Taxonomy, code 2080N0001X
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 | |
|---|---|---|---|---|
| 2080N0001X | Neonatal-Perinatal Medicine Physician Neonatal-Perinatal Medicine | 028038 | CT | primary |
| 208000000X | Pediatrics Physician | 028038 | CT |
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 | 1912926908 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jul 19, 2006 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | No |
| Credential | MD |
| Practice address |
5 PERRYRIDGE ROAD GREENWICH HOSPITAL Greenwich, CT 06830 (203) 863-3515 Fax (203) 863-3816 |
| Mailing address |
PO BOX 673 Old Greenwich, CT 06870 |
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 | 1 | 2 | 9 | 2 | 6 | 9 | 0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 9 | 2 | 2 | 9 | 2 | 3 | 9 | 0 |
Sum = 62 · next multiple of 10 = 70 · check digit = 8 · actual last digit = 8
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.