Mark D. Shields, MD
NPI 1366411555ActiveIndividual· Internal Medicine· Laguna Hills, CA
Internal Medicine (MD) in Laguna Hills, California, trained at University of California, Geffen School of Medicine (class of 1992). Their prescriptions cost Medicare Part D more than their services did: $424,436 for 7,598 claims, against $78,186 paid for services in 2024.
Overview
| NPI | 1366411555 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Mar 17, 2006 |
| Last updated in NPPES | Nov 28, 2025 |
| Certified by provider | Nov 28, 2025 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | G77342 | 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 - Internal Medicine (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 248 |
|---|---|
| Services billed | 1,153 across 46 procedure codes |
| Paid by Medicare | $78,186 |
Part D prescriptions in 2024
| Prescriptions (claims) | 7,598 · 17,176 30-day fills |
|---|---|
| Patients | 586 |
| Total drug cost | $424,436 |
| Generic share | 91% of claims |
Education and affiliations
| Medical school | University of California, Geffen School of Medicine |
|---|---|
| Graduation year | 1992 |
| Medicare specialty | Internal Medicine |
Medical groups
- Healthcare Partners Affiliates Medical GroupAnaheim, CA · 754 clinicians
- Paloma Medical Group IncSan Juan Capistrano, CA · 19 clinicians
Hospital affiliations
- Hoag Memorial Hospital PresbyterianNewport Beach, CA
- Memorialcare Saddleback Medical CenterLaguna Hills, CA
Other facilities
- Care Plus Home HealthHome health agency · Laguna Hills, CA
- Hoag Home HealthHome health agency · Newport Beach, CA
Industry payments (Open Payments)
None reported for 2025 or 2024.
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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