Mark O'Brien, MD
NPI 1124129267 · Family Medicine Physician · Carmel, IN
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark O'Brien, MD is a Family Medicine Physician provider in Carmel, IN (NPI 1124129267).
Provider details
- NPI number
- 1124129267
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 01037757A (IN)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
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
2 documented practice locations
- Medicare service volume (vs. specialty peers)28% of score
596 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 | 415 | $119 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 88 | $84 |
| Administration of Influenza Virus VaccineG0008 | 36 | $30 |
| Hemoglobin A1c Level83036 | 24 | $10 |
| Automated Urinalysis Test81003 | 18 | $2 |
| Administration of Pneumococcal VaccineG0009 | 15 | $30 |
Typical Medicare-allowed amounts for these services range $2–$119 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 88 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 686 | 185 |
| Amlodipine Besylate | 355 | 101 |
| Losartan Potassium | 262 | 73 |
| Lisinopril | 233 | 63 |
| Metoprolol Succinate | 221 | 58 |
| Levothyroxine Sodium | 205 | 53 |
| Metformin Hcl |
Practice location
Mailing address
Additional practice locations (1)
- 409 E Washington StButler, IN 46721-1175Phone: (260) 868-5843Fax: (260) 868-5844
Registry dates
- Enumerated
- 2006-09-25
- Last updated
- 2021-01-06
- Certified
- 2021-01-06
Frequently asked questions
- What is Mark O'Brien's NPI number?
- Mark O'Brien's National Provider Identifier (NPI) is 1124129267, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark O'Brien's specialty?
- Mark O'Brien is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mark O'Brien located?
- Mark O'Brien's practice location on file with NPPES is 11725 N Illinois St Ste 250, Carmel, IN 46032-3015.
- What is Mark O'Brien's phone number?
- The practice phone number listed in the NPPES registry for Mark O'Brien is (317) 688-5300.
- Does Mark O'Brien accept Medicare?
- Mark O'Brien is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark O'Brien's NPI active?
- Yes — Mark O'Brien's NPI (1124129267) is active in the NPPES registry as of the last update on 2021-01-06.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.