John Allen, M.D.
NPI 1023436839 · Internal Medicine Physician · Baltimore, MD
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Allen, M.D. is a Internal Medicine Physician provider in Baltimore, MD (NPI 1023436839).
Provider details
- NPI number
- 1023436839
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- D83158 (MD)
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
12 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
685 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 Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 259 | $108 |
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 198 | $17 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 74 | $158 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 48 | $89 |
| Administration of Influenza Virus VaccineG0008 | 28 | $29 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 58 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 152 | 56 |
| Amlodipine Besylate | 127 | 45 |
| Metoprolol Succinate | 59 | 20 |
| Losartan Potassium | 58 | 25 |
| Gabapentin | 56 | 18 |
| Lisinopril | 56 | 22 |
| Levothyroxine Sodium |
Practice location
Mailing address
Registry dates
- Enumerated
- 2014-03-31
- Last updated
- 2021-11-30
- Certified
- 2021-11-30
Frequently asked questions
- What is John Allen's NPI number?
- John Allen's National Provider Identifier (NPI) is 1023436839, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Allen's specialty?
- John Allen is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is John Allen located?
- John Allen's practice location on file with NPPES is 22 S Greene St, Baltimore, MD 21201.
- What is John Allen's phone number?
- The practice phone number listed in the NPPES registry for John Allen is (672) 141-5156.
- Does John Allen accept Medicare?
- John Allen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Allen's NPI active?
- Yes — John Allen's NPI (1023436839) is active in the NPPES registry as of the last update on 2021-11-30.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.