Mark Ritter, M.D.
NPI 1609939511 · Internal Medicine Physician · Chesterton, IN
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Ritter, M.D. is a Internal Medicine Physician provider in Chesterton, IN (NPI 1609939511).
Provider details
- NPI number
- 1609939511
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 01037402A (IN)
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
541 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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 358 | $120 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 110 | $122 |
| Telephone Medical Discussion With Physician, 21-30 Minutes99443 | 25 | $120 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 19 | $156 |
| Annual Wellness Visit; Includes a Personalized Prevention Plan of Service (pps), Initial VisitG0438 | 17 | $155 |
| Administration of Influenza Virus VaccineG0008 | 12 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 106 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 653 | 183 |
| Amlodipine Besylate | 575 | 158 |
| Rosuvastatin Calcium | 532 | 154 |
| Lisinopril | 382 | 113 |
| Pantoprazole Sodium | 285 | 87 |
| Metformin Hcl | 283 | 81 |
| Levothyroxine Sodium |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$38 across 1 record (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
- 2006-12-19
- Last updated
- 2020-09-14
- Certified
- 2020-09-14
Frequently asked questions
- What is Mark Ritter's NPI number?
- Mark Ritter's National Provider Identifier (NPI) is 1609939511, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Ritter's specialty?
- Mark Ritter is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Ritter located?
- Mark Ritter's practice location on file with NPPES is 2022 Kelle Dr, Chesterton, IN 46304-8708.
- What is Mark Ritter's phone number?
- The practice phone number listed in the NPPES registry for Mark Ritter is (219) 395-2200.
- Does Mark Ritter accept Medicare?
- Mark Ritter is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Ritter's NPI active?
- Yes — Mark Ritter's NPI (1609939511) is active in the NPPES registry as of the last update on 2020-09-14.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.