Mark Johnson, MD
NPI 1013923127 · Internal Medicine Physician · Mason City, IA
Enrolled with Medicare as Practitioner - Endocrinology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Johnson, MD is a Internal Medicine Physician provider in Mason City, IA (NPI 1013923127).
Provider details
- NPI number
- 1013923127
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 21527 (IA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
3,849 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
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 .
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) |
|---|---|---|
| Routine Electrocardiogram (ecg) Using at Least 12 Leads With Interpretation and Report Only93010 | 1,381 | $7 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 987 | $90 |
| 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 | 828 | $15 |
| Continuous Monitoring of Blood Sugar Level in Tissue Fluid Using Sensor Under Skin With Interpretation and Report95251 | 379 | $32 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 244 | $72 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 93 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Semaglutidebrand: Ozempic | 1,205 | 170 |
| Empagliflozinbrand: Jardiance | 749 | 125 |
| Insulin Aspartbrand: Novolog Flexpen | 492 | 130 |
| Insulin Glargine/Lixisenatidebrand: Soliqua 100-33 | 475 | 68 |
| Dulaglutidebrand: Trulicity | 381 | 54 |
| Empagliflozin/Metformin Hclbrand: Synjardy Xr | 344 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$16,974 across 47 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-07-31
- Last updated
- 2025-07-08
- Certified
- 2025-07-08
Frequently asked questions
- What is Mark Johnson's NPI number?
- Mark Johnson's National Provider Identifier (NPI) is 1013923127, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Johnson's specialty?
- Mark Johnson is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Johnson located?
- Mark Johnson's practice location on file with NPPES is 910 N Eisenhower Ave, Mason City, IA 50401-2800.
- What is Mark Johnson's phone number?
- The practice phone number listed in the NPPES registry for Mark Johnson is (641) 428-7799.
- Does Mark Johnson accept Medicare?
- Mark Johnson is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Johnson's NPI active?
- Yes — Mark Johnson's NPI (1013923127) is active in the NPPES registry as of the last update on 2025-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.