Mark Sierra, MD
Mark Sierra, MD is a Cardiovascular Disease Physician in West Branch, MI, registered under NPI 1639381593.
Getting there
The practice address on file is 2431 S. M-30, West Branch, MI 48661. 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 |
|---|---|---|
| 4301086565 | MI | Cardiovascular Disease Physician primary |
This provider holds licence 4301086565 issued in MI. 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 - Cardiovascular Disease (cardiology)
- PAC ID
- 9032281613
- Enrollment ID
- I20080627000038
Medicare enrolment is recorded as approved under the provider type Practitioner - Cardiovascular Disease (cardiology). Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
What Cardiovascular Disease covers
An internist who specializes in diseases of the heart and blood vessels and manages complex cardiac conditions such as heart attacks and life-threatening, abnormal heartbeat rhythms. NUCC Health Care Provider Taxonomy, code 207RC0000X
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 | 1639381593 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | May 4, 2007 |
| Last updated | Apr 25, 2012 |
| Status | Active |
| Sole proprietor | No |
| Gender | Male |
| Credential | MD |
| Practice address |
2431 S. M-30 West Branch, MI 48661 (989) 343-3264 Fax (989) 343-3202 |
| Mailing address |
401 S. BELLENGER HWY Flint, MI 48532 |
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 | 6 | 3 | 9 | 3 | 8 | 1 | 5 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 6 | 9 | 6 | 8 | 2 | 5 | 9 |
Sum = 77 · next multiple of 10 = 80 · check digit = 3 · actual last digit = 3
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.