Alison Mercier, MD
Alison Mercier, MD is a Geriatric Medicine (Family Medicine) Physician in Lancaster, PA, registered under NPI 1811481997.
Getting there
The practice address on file is 2112 HARRISBURG PIKE STE 312, Lancaster, PA 17601. 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 |
|---|---|---|
| MD486393 | PA | Geriatric Medicine (Family Medicine)… primary |
This provider holds licence MD486393 issued in PA. 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 - Family Practice
- PAC ID
- 8628329950
Enrolled in Medicare 2 times, across 2 states:
| State | Enrollment ID | Provider type |
|---|---|---|
| Vermont | I20220822002482 | Practitioner - Family Practice |
| Pennsylvania | I20241114000601 | Practitioner - Family Practice |
Medicare enrolment is recorded as approved under the provider type Practitioner - Family Practice. There are 2 separate enrolment records across 2 states (VT, PA). Multiple enrolments usually mean the provider bills Medicare from more than one practice location, or has kept an earlier enrolment after moving. Each record carries its own enrolment ID, listed above. 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 Geriatric Medicine covers
A family medicine physician with special knowledge of the aging process and special skills in the diagnostic, therapeutic, preventive and rehabilitative aspects of illness in the elderly. This specialist cares for geriatric patients in the patient's home, the office, long-term care settings such as nursing homes, and the hospital. NUCC Health Care Provider Taxonomy, code 207QG0300X
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 | 1811481997 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jun 21, 2018 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | No |
| Credential | MD |
| Practice address |
2112 HARRISBURG PIKE STE 312 Lancaster, PA 17601 (802) 999-6433 |
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 | 8 | 1 | 1 | 4 | 8 | 1 | 9 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 8 | 2 | 1 | 8 | 8 | 2 | 9 | 9 |
Sum = 73 · next multiple of 10 = 80 · check digit = 7 · actual last digit = 7
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.