Gregory Johnson, MD
NPI 1942213509 · Internal Medicine Physician · Somerville, MA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Gregory Johnson, MD is a Internal Medicine Physician provider in Somerville, MA (NPI 1942213509).
Provider details
- NPI number
- 1942213509
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 151587 (MA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
2,074 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 447 | $89 |
| Detection Test By Immunoassay With Direct Visual Observation for Influenza Virus87804 | 338 | $16 |
| Detection Test By Immunoassay Technique for Severe Acute Respiratory Syndrome Coronavirus87426 | 166 | $35 |
| Insertion of Needle Into Vein for Collection of Blood Sample36415 | 132 | $9 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 128 | $132 |
| Complete Blood Cell Count (red Cells, White Blood Cell, Platelets), Automated Test and Automated Differential White Blood Cell Count85025 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 21 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Doxycycline Monohydrate | 67 | 67 |
| Prednisone | 63 | 61 |
| Amoxicillin/Potassium Clavbrand: Amoxicillin-Clavulanate Potass | 45 | 45 |
| Cephalexin | 32 | 32 |
| Nitrofurantoin Monohyd/M-Crystbrand: Nitrofurantoin Mono-Macro | 31 | 30 |
| Cyclobenzaprine Hcl | 24 | 24 |
| Amoxicillin | 22 | 22 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-08-14
- Last updated
- 2021-02-18
- Certified
- 2021-02-18
Frequently asked questions
- What is Gregory Johnson's NPI number?
- Gregory Johnson's National Provider Identifier (NPI) is 1942213509, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Gregory Johnson's specialty?
- Gregory Johnson is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Gregory Johnson located?
- Gregory Johnson's practice location on file with NPPES is 40 Holland St, Somerville, MA 02144-2705.
- What is Gregory Johnson's phone number?
- The practice phone number listed in the NPPES registry for Gregory Johnson is (617) 629-6350.
- Does Gregory Johnson accept Medicare?
- Gregory Johnson is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Gregory Johnson's NPI active?
- Yes — Gregory Johnson's NPI (1942213509) is active in the NPPES registry as of the last update on 2021-02-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.