Quick answers
- Does Mary K. Hahn accept Medicare assignment?
- Yes. Medicare's clinician data says Mary K. Hahn accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does Mary K. Hahn see?
- In 2024, CMS data shows 529 Original Medicare patients and 707 services for Mary K. Hahn. This counts Original Medicare only and measures volume, not quality.
- What is Mary K. Hahn's NPI number?
- 1275021081. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for Mary K. Hahn, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 529 |
|---|---|
| Services billed to Medicare | 707 |
| Different services or procedures | 20 |
| Participating Medicare provider | Yes |
| Average age of these patients | 78 |
Most frequent services
- Initial hospital care with straightforward or low level of medical decision making, per day, if using time, at least 40 minutes (99221)135 services
- Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes (99222)111 services
- Subsequent hospital care with straightforward or low level of medical decision making, per day, if using time, at least 25 minutes (99231)89 services
- Telehealth consultation, critical care, initial , physicians typically spend 60 minutes communicating with the patient and providers via telehealth (G0508)53 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)52 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- High blood pressure75%
- High cholesterol75%
- Stroke or mini-stroke73%
- Ischemic heart disease60%
- Arthritis58%
- Diabetes48%
Hospitals where Mary K. Hahn works
Medicare's Facility Affiliation Data lists Mary K. Hahn at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- Long Island Community HospitalPatchogue, NY · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 330141
- Suny/Stony Brook University HospitalStony Brook, NY · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 330393
Practice locations
Addresses where Mary K. Hahn is enrolled with Medicare (CMS data updated October 2, 2026).
- 100 Nicolls RdStony Brook, NY 11794 (631) 444‑2599
- Lauterbur DrStony Brook, NY 11794 (631) 638‑1000
Group practices
Medicare enrollment lists Mary K. Hahn as a member of this group (CMS data updated October 2, 2026).
- Neurology Associates of Stony Brook, University Faculty Practice Corpo57 clinicians in the group
Specialties
- Neurologyprimary
Other neurologists in Stony Brook
Clinicians with the same Medicare primary specialty in Stony Brook, NY — not a recommendation.
Other clinicians in Neurology Associates of Stony Brook, University Faculty Practice Corpo
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 2023 (3 years since medical school) |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1275021081 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians