Freddie Mertzig, APNP
Freddie Mertzig, APNP is a Gerontology Nurse Practitioner in Milwaukee, WI, registered under NPI 1922523836. 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 3237 S 16TH ST, Milwaukee, WI 53215. 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 |
|---|---|---|
| 7889-33 | WI | Gerontology Nurse Practitioner primary |
| 7889-33 | WI | Nurse Practitioner |
This provider holds licence 7889-33 issued in WI. 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
- 5294091583
- Enrollment ID
- I20171101002854
Medicare enrolment is recorded as approved under the provider type Practitioner - Nurse Practitioner. 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 Gerontology covers
Definition to come... NUCC Health Care Provider Taxonomy, code 363LG0600X
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 | |
|---|---|---|---|---|
| 363LG0600X | Gerontology Nurse Practitioner Gerontology | 7889-33 | WI | primary |
| 363L00000X | Nurse Practitioner | 7889-33 | WI |
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 | 1922523836 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Aug 11, 2017 |
| Last updated | Sep 25, 2017 |
| Status | Active |
| Sole proprietor | No |
| Credential | APNP |
| Practice address |
3237 S 16TH ST Milwaukee, WI 53215 (262) 647-5000 |
| Mailing address |
1224 N PROSPECT AVE APT 7S Milwaukee, WI 53202 |
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 | 9 | 2 | 2 | 5 | 2 | 3 | 8 | 3 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 9 | 4 | 2 | 1 | 2 | 6 | 8 | 6 |
Sum = 64 · next multiple of 10 = 70 · check digit = 6 · actual last digit = 6
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.