Hakan Ay, MD
Hakan Ay, MD is a Vascular Neurology Physician in Charlestown, MA, registered under NPI 1184140162. 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 MASS GENERAL HOSPITAL, 13TH STREET BUILDING 149-2303, Charlestown, MA 02129. 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 |
|---|---|---|
| 91AB030 | ZZ | Vascular Neurology Physician primary |
This provider holds licence 91AB030 issued in ZZ. 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 Vascular Neurology covers
Vascular Neurology is a subspecialty in the evaluation, prevention, treatment and recovery from vascular diseases of the nervous system. This subspecialty includes the diagnosis and treatment of vascular events of arterial or venous origin from a large number of causes that affect the brain or spinal cord such as ischemic stroke, intracranial hemorrhage, spinal cord ischemia and spinal cord hemorrhage. NUCC Health Care Provider Taxonomy, code 2084V0102X
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 | 1184140162 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Aug 21, 2017 |
| Last updated | Jul 21, 2022 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | MD |
| Practice address |
MASS GENERAL HOSPITAL, 13TH STREET BUILDING 149-2303 Charlestown, MA 02129 (617) 724-4507 |
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 | 8 | 4 | 1 | 4 | 0 | 1 | 6 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 1 | 7 | 4 | 2 | 4 | 0 | 1 | 3 |
Sum = 48 · next multiple of 10 = 50 · check digit = 2 · actual last digit = 2
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.