Marissa Niemeyer, MSN, AGPCNP-C
Marissa Niemeyer, MSN, AGPCNP-C is a Gerontology Nurse Practitioner in Grand Rapids, MI, registered under NPI 1003485194.
Getting there
The practice address on file is 145 MICHIGAN ST NE STE 3410, Grand Rapids, MI 49503. 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 |
|---|---|---|
| 4704330088 | MI | Gerontology Nurse Practitioner primary |
This provider holds licence 4704330088 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 - Nurse Practitioner
- PAC ID
- 6901208040
Medicare enrolment is recorded as approved under the provider type Practitioner - Nurse Practitioner. 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 Gerontology covers
Definition to come... NUCC Health Care Provider Taxonomy, code 363LG0600X
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 | 1003485194 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jun 22, 2021 |
| Last updated | Jan 31, 2025 |
| Status | Active |
| Sole proprietor | No |
| Credential | MSN, AGPCNP-C |
| Practice address |
145 MICHIGAN ST NE STE 3410 Grand Rapids, MI 49503 (616) 391-9945 |
| Mailing address |
100 MICHIGAN ST NE # MC845 Grand Rapids, MI 49503 |
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 | 4 | 8 | 5 | 1 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 0 | 3 | 8 | 8 | 1 | 1 | 9 |
Sum = 56 · next multiple of 10 = 60 · check digit = 4 · actual last digit = 4
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.