Quick answers
- Does John K. Oppenheimer accept Medicare assignment?
- Yes. Medicare's clinician data says John K. Oppenheimer 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 John K. Oppenheimer see?
- In 2024, CMS data shows 197 Original Medicare patients and 793 services for John K. Oppenheimer. This counts Original Medicare only and measures volume, not quality.
- What is John K. Oppenheimer's NPI number?
- 1659364214. 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 John K. Oppenheimer, 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 | 197 |
|---|---|
| Services billed to Medicare | 793 |
| Different services or procedures | 14 |
| Participating Medicare provider | Yes |
| Average age of these patients | 81 |
Most frequent services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)311 services
- Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)141 services
- Influenza vaccine split virus, preservative free (90662)84 services
- Administration of influenza virus vaccine (G0008)82 services
- Pneumococcal conjugate vaccine, 20 valent (pcv20), for intramuscular use (90677)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 cholesterol75%
- High blood pressure59%
- Arthritis40%
- Ischemic heart disease30%
- Atrial fibrillation20%
- Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)19%
Hospitals where John K. Oppenheimer works
Medicare's Facility Affiliation Data lists John K. Oppenheimer 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.
- 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 John K. Oppenheimer is enrolled with Medicare (CMS data updated October 2, 2026).
- 60 Bay StSag Harbor, NY 11963 (631) 725‑4600
Specialties
- Internal Medicineprimary
- Geriatric Medicinealso
Other internal medicine doctors in New York
Clinicians with the same Medicare primary specialty in New York — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Tulane University School Of Medicine |
| Graduation year | 1981 (45 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1659364214 |
| 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