Michelle Johnson, MD
Michelle Johnson, MD is a Geriatric Medicine (Internal Medicine) Physician in Cambridge, MA, registered under NPI 1114285905. This provider registers 4 separate taxonomy codes, which usually means they practise across more than one recognised specialty. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 119 WINDSOR ST, Cambridge, MA 02139. 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 |
|---|---|---|
| 265139 | MA | Geriatric Medicine (Internal Medicine)… primary |
| 265139 | MA | Skilled Nursing Facility |
| 265139 | MA | Primary Care Clinic/Center |
| 265139 | MA | Family Medicine Physician |
This provider holds licence 265139 issued in MA. 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 - Geriatric Medicine
- PAC ID
- 6709001092
Medicare enrolment is recorded as approved under the provider type Practitioner - Geriatric Medicine. 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 Geriatric Medicine covers
An internist who has 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 207RG0300X
All registered taxonomy codes
This provider registers 4 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207RG0300X | Geriatric Medicine (Internal Medicine) Physician Geriatric Medicine | 265139 | MA | primary |
| 314000000X | Skilled Nursing Facility | 265139 | MA | |
| 261QP2300X | Primary Care Clinic/Center Primary Care | 265139 | MA | |
| 207Q00000X | Family Medicine Physician | 265139 | MA |
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 | 1114285905 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Apr 30, 2012 |
| Last updated | Dec 19, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | MD |
| Practice address |
119 WINDSOR ST Cambridge, MA 02139 (617) 665-3600 |
| Mailing address |
10 BEACON ST Somerville, MA 02143 |
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 | 1 | 1 | 4 | 2 | 8 | 5 | 9 | 0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 1 | 2 | 4 | 4 | 8 | 1 | 9 | 0 |
Sum = 55 · next multiple of 10 = 60 · check digit = 5 · actual last digit = 5
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.