Grayson Halladay, PA-C
Grayson Halladay, PA-C is a Surgical Physician Assistant in Phoenix, AZ, registered under NPI 1225589021. 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 9321 W THOMAS RD STE 205, Phoenix, AZ 85037. 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 |
|---|---|---|
| 6575 | AZ | Surgical Physician Assistant primary |
This provider holds licence 6575 issued in AZ. 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 - Physician Assistant
- PAC ID
- 8820378730
Medicare enrolment is recorded as approved under the provider type Practitioner - Physician Assistant. This means the provider is enrolled to bill Medicare, though it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
What Surgical covers
Definition to come... NUCC Health Care Provider Taxonomy, code 363AS0400X
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 | |
|---|---|---|---|---|
| 363AS0400X | Surgical Physician Assistant Surgical | 6575 | AZ | primary |
| 363A00000X | Physician Assistant | — | — |
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 | 1225589021 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Oct 18, 2016 |
| Last updated | Aug 13, 2025 |
| Status | Active |
| Sole proprietor | No |
| Credential | PA-C |
| Practice address |
9321 W THOMAS RD STE 205 Phoenix, AZ 85037 (866) 974-2673 Fax (866) 939-2673 |
| Mailing address |
18444 N 25TH AVE STE 310 Phoenix, AZ 85023 |
| Other identifiers |
212451
(AZ) |
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 | 2 | 2 | 5 | 5 | 8 | 9 | 0 | 2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 2 | 4 | 5 | 1 | 8 | 9 | 0 | 4 |
Sum = 59 · next multiple of 10 = 60 · check digit = 1 · actual last digit = 1
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.