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Edit this profileAt a glance
- 604 Main St, Shrewsbury, MA 01545
About Dr. O'brien
Based in Shrewsbury, MA, Mary C. O'Brien, M.D. is listed in the NPI registry under internal medicine. Mary graduated from State University of New York at Stony Brook, School of Medicine in 1991. According to Medicare claims data, Mary cared for 450 Medicare patients across 664 services. The services billed most often include established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more, established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more, and routine electrocardiogram (ecg) using at least 12 leads with tracing. NPI 1912980434 identifies this record in the national registry.
Factual summary compiled by Guide.md from public records; not written by this provider.
Education & Training
Specialty
Credentials & Licensing
Medicare information
Exactly as CMS reports it (National Downloadable File, Opt-Out Affidavits, Order & Referring). Not an insurance directory; confirm coverage with the office.
Contact Information
- (508) 842-0057
- Email not available
Practice Locations
604 MAIN ST
Shrewsbury, MA 01545
Conditions Commonly Evaluated or Treated
Within Internal Medicine generally. Availability varies by clinician, training and location — this profile has not been claimed, so nothing here is a personal claim by the provider.
Conditions
Cancer Prevention
Cancer risk
Environmental health
- Asbestos Exposure
- Contaminated drinking water exposure
- Heat exhaustion and heat stroke
- Radon gas exposure
- Tick bite and Lyme disease risk
- Toxic Mold Exposure
- Wildfire smoke and air pollution exposure
- Workplace Chemical Exposure
General wellness
Heart health
Infectious Disease
Infectious disease
Kidney health
Lifestyle & wellness
Lifestyle health
Longevity
Metabolic & Lifestyle
Occupational health
Occupational Health
Rashes & allergy
Sexual Health
Sexual health
Substance use
Travel health
Wellness and energy
Workplace health
Most searched conditions
Cardiometabolic
Digestive and liver
Endocrine, blood, and bone
Kidney and urinary
Respiratory
Blood & Circulation
Blood disorders
Brain & Nerves
Brain and nerves
Cardiac and vascular
Digestive
Heart & Circulation
Infections
Kidney & Bladder
Lungs & Breathing
Mental Health
Neurologic and behavioral
Pain
Rheumatologic and pain
Procedures & services
Addiction & habits
Cancer screening
Cancer Screening
Checkups & exams
Chronic illness
Diagnostics & screening
Environmental health
Fitness & body composition
Heart & Circulation
- Blood Pressure Check
- Heart monitor
Heart & circulation
Heart health
Hospital-based procedures
Imaging referral
Immunizations
Infection & Microbiology Tests
- STI and STD Screening
- H. Pylori Breath Test
Lifestyle & Prevention
Longevity
Lower endoscopy
Lungs & Breathing
Metabolic & Weight
Metabolic health
Occupational health
Occupational Health
Office Procedures
Preventive and evaluation
- Preoperative medical clearance
- Medication management
- Post-hospital transitional care
Preventive imaging
Preventive screening
Routine Blood Tests
Screening & labs
Screening and diagnostic testing
- Blood pressure screening
- Cancer screening and prevention planning
- Diabetes and prediabetes screening
- EKG
- Spirometry
Screenings & Diagnostics
Travel Health
Travel medicine
Wellness
Wellness & Screening
Workplace health
Skin growths
Sleep
Most searched procedures
Bones & Joints
Brain and nerves
Digestive
- Endoscopy
Exams & Consultations
Lab tests
Minor procedures
- Ingrown toenail removal
- Suture removal
Office procedures
Pain management
Preventive & Routine Care
Sexual health
Procedures Most Often Billed to Medicare
664 services · 450 patients · 9 distinct codes
| Procedure | Type | Code | Services | Compared with peers |
|---|---|---|---|---|
| Routine electrocardiogram (ecg) using at least 12 leads with tracing | Treatment | 93005 |
58 | More often than most peers in Internal Medicine |
| Influenza vaccine, trivalent, 0.5 ml dosage | Treatment | 90658 |
34 | As often as other peers in Internal Medicine |
| Pneumococcal conjugate vaccine, 20 valent (pcv20), for intramuscular use | Treatment | 90677 |
14 | Less often than most peers in Internal Medicine |
| Influenza vaccine, inactivated | Treatment | 90653 |
12 | Less often than most peers in Internal Medicine |
| Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more | Office visit | 99214 |
406 | More often than most peers in Internal Medicine |
| Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more | Office visit | 99213 |
60 | As often as other peers in Internal Medicine |
| Administration of influenza virus vaccine | Billing code | G0008 |
47 | As often as other peers in Internal Medicine |
| 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' | Billing code | G2211 |
19 | Less often than most peers in Internal Medicine |
| Administration of pneumococcal vaccine | Billing code | G0009 |
14 | Less often than most peers in Internal Medicine |
Source: CMS Medicare public data. Shows how often procedures were billed — not quality of care or patient satisfaction.
Related providers
Connections drawn from the registry and from what providers have told us. A link here is not a referral or an endorsement.
Other internists at this location 4
Same specialty, same street address — most likely the same department or group.
Related specialists at this location 8
Clinically related specialties at the same address — the people this provider most likely works alongside.
Also at this address 2
Providers at the same street address. Each files their own registry entry, so a shared practice often appears under several different names.
More connections — 31 related providers in 4 groups
Other internists in Shrewsbury 7
Same specialty, same city.
Trained at State University of New York at Stony Brook, School of Medicine 8
Other providers in the same specialty who trained at the same institution.
Class of 1991 at State University of New York at Stony Brook, School of Medicine 8
Providers who graduated from the same medical school in the same year.
Also performs Routine electrocardiogram (ecg) using at least 12 leads with tracing 8
Providers in MA who bill this service to Medicare most often.
Common questions
What kind of doctor is Mary C. O'Brien?
Mary C. O'Brien is an internist in Shrewsbury, MA. That is the designation recorded for this NPI in the federal registry, where it is listed as “Internal Medicine”.
NPI registry
What is Mary C. O'Brien's address?
Mary C. O'Brien is listed at 604 Main St, Shrewsbury, MA 01545. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
How can I make an appointment with Mary C. O'Brien?
The number on file is (508) 842-0057. Contact the office directly to confirm availability and scheduling.
NPI registry
What is Mary C. O'Brien's NPI number?
Mary C. O'Brien's National Provider Identifier is 1912980434. It is issued by the Centers for Medicare & Medicaid Services and is unique and permanent — it does not change if they move practice.
NPI registry
Where did Mary C. O'Brien train?
Mary C. O'Brien attended State University of New York at Stony Brook, School of Medicine, graduating in 1991. This comes from the CMS National Downloadable File.
CMS public data
How long has Mary C. O'Brien been practicing?
Mary C. O'Brien has 35 years experience. Calculated from a graduation year of 1991, reported in the CMS National Downloadable File.
CMS public data
What procedures does Mary C. O'Brien perform?
According to Medicare billing data, Mary C. O'Brien provides treatments such as routine electrocardiogram using at least 12 leads with tracing and influenza vaccine, trivalent, 0.5 ml dosage, alongside routine visits and testing. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has Mary C. O'Brien confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Mary C. O'Brien. If this is you, claiming it is free.
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