Michael S. Greenfield, M.D.
NPI 1295873685ActiveIndividual· Internal Medicine, Endocrinology, Diabetes & Metabolism· Mountain View, CA
Internal Medicine, Endocrinology, Diabetes & Metabolism (M.D.) in Mountain View, California, trained at Harvard Medical School (class of 1974). Their prescriptions cost Medicare Part D more than their services did: $945,708 for 2,776 claims, against $76,355 paid for services in 2024. Amgen Inc. was the largest of 6 companies reporting payments in 2025, $217.07 in all, mostly food and beverage.
Overview
| NPI | 1295873685 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | Yes |
| NPI issued | Feb 1, 2007 |
| Last updated in NPPES | Jul 8, 2007 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Endocrinology, Diabetes & Metabolism Primary | 207RE0101X | G35253 | CA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Oct 9, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 10, 2026 | No match | — |
| New York OMIG · Nov 10, 2026 | No match | — |
| Ohio Medicaid · Nov 10, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 10, 2026 | No match | — |
| Washington HCA · Nov 10, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Endocrinology (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 216 |
|---|---|
| Services billed | 737 across 12 procedure codes |
| Paid by Medicare | $76,355 |
Part D prescriptions in 2024
| Prescriptions (claims) | 2,776 · 6,726 30-day fills |
|---|---|
| Patients | 234 |
| Total drug cost | $945,708 |
| Generic share | 62% of claims |
Education and affiliations
| Medical school | Harvard Medical School |
|---|---|
| Graduation year | 1974 |
| Medicare specialty | Endocrinology |
| Secondary specialties | Internal Medicine |
| Telehealth | Offers telehealth |
Hospital affiliation
- El Camino HealthMountain View, CA
Industry payments (Open Payments)
- 2025$217.07 · 10 payments from 6 companies
- 2024$99.96 · 6 payments from 3 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Amgen Inc. | $75.13 | 3 |
| Madrigal Pharmaceuticals | $46.80 | 2 |
| Abbott Laboratories | $35.12 | 2 |
| Neurocrine Biosciences, Inc. | $24.04 | 1 |
| Agios Pharmaceuticals, Inc. | $19.98 | 1 |
What the 2025 payments were for
- Food and Beverage$193.03 · 9 payments
- Education$24.04 · 1 payment
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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