Melissa Callahan, CRNP
Melissa Callahan, CRNP is a Gerontology Nurse Practitioner in Exton, PA, registered under NPI 1669411393. 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 320 EXTON CMNS, Exton, PA 19341. 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 |
|---|---|---|
| TP006181H | PA | Gerontology Nurse Practitioner primary |
| TP006182C | PA | Adult Health Nurse Practitioner |
This provider holds licence TP006181H issued in PA. 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 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 | TP006181H | PA | primary |
| 363LA2200X | Adult Health Nurse Practitioner Adult Health | TP006182C | PA |
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 | 1669411393 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jun 6, 2006 |
| Last updated | Feb 26, 2024 |
| Status | Active |
| Sole proprietor | No |
| Credential | CRNP |
| Practice address |
320 EXTON CMNS Exton, PA 19341 (866) 268-6609 Fax (866) 610-4542 |
| Other identifiers |
102510472 0001
· Other (PA) 032688YCCW · Other (PA) |
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 | 6 | 9 | 4 | 1 | 1 | 3 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 3 | 9 | 8 | 1 | 2 | 3 | 9 |
Sum = 67 · next multiple of 10 = 70 · 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.