Patrick Day, MD
Patrick Day, MD is a Pediatric Cardiology Physician in Austin, TX, registered under NPI 1003376138.
Getting there
The practice address on file is 4900 MUELLER BLVD, Austin, TX 78723. 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 |
|---|---|---|
| T6547 | TX | Pediatric Cardiology Physician primary |
This provider holds licence T6547 issued in TX. 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 Pediatric Cardiology covers
A pediatric cardiologist provides comprehensive care to patients with cardiovascular problems. This specialist is skilled in selecting, performing and evaluating the structural and functional assessment of the heart and blood vessels, and the clinical evaluation of cardiovascular disease. NUCC Health Care Provider Taxonomy, code 2080P0202X
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 | 1003376138 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Mar 24, 2019 |
| Last updated | Jun 4, 2026 |
| Status | Active |
| Sole proprietor | No |
| Credential | MD |
| Practice address |
4900 MUELLER BLVD Austin, TX 78723 (512) 324-0000 |
| Mailing address |
5904 AYLFORD CT Austin, TX 78739 |
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 | 0 | 0 | 3 | 3 | 7 | 6 | 1 | 3 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 0 | 3 | 6 | 7 | 3 | 1 | 6 |
Sum = 52 · next multiple of 10 = 60 · 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.