DR. GEMMA GUILLERMO (M.D.) – Psychiatry Physician, NPI 1831154418
Psychiatry Physician
Main info
Doctor Profile
Profile Insights
NPPES metrics only — not quality of care.
4,134 PSYCHIATRY in CA
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Provider Addresses for DR. GEMMA GUILLERMO (M.D.)
2290, Vera Avenue, Redwood City, San Mateo County, California, 94062, United States
REDWOOD CITY, CA 940611346
Phone:
Type: Mailing
Sequoia Hospital, 170, Alameda de las Pulgas, Redwood City, San Mateo County, California, 94062, United States
1EAST, SEQUOIA HOSPITAL
REDWOOD CITY, CA 940622799
Phone: (650) 367-5559
Fax: (650) 368-3754
Type: Location
NPPES updates history
No NPPES updates recorded for this provider.
Prescription Activity
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Open Payments (CMS)
CMS reports 7 Open Payments records for all available years, with a total value of $840.
Total Amount is formed as General ($840) + Research ($0) + Ownership ($0) = $840.
Last reported payment date: 2024-11-14 • Largest payer in this snapshot: Alkermes, Inc. ($452).
Total Amount
$840
General + Research + Ownership
Payments
7
Total payment records
General Amount
$840
General payments
Research Amount
$0
Research funding
Ownership Amount
$0
Ownership interests
Ownership Count
0
Ownership records
Last Payment Date
2024-11-14
Latest reported date
Top Companies
Largest payers in this snapshot
| Company | Amount |
|---|---|
| Alkermes, Inc. | $452 |
| Teva Pharmaceuticals USA, Inc. | $239 |
| Janssen Pharmaceuticals, Inc | $150 |
Medicare Enrollment & Revalidation
Source: CMS public data · Not endorsed by CMS ·
Educational use only—not medical, billing, or legal advice.
PECOS enrollment status
Participating (accepts Medicare assignment)
Enrollment effective: 2004-11-08
PECOS data refreshed: 2026-05-27
Medicare revalidation (CMS due date list)
Due date not assigned yet
CMS is tracking this Medicare enrollment for revalidation, but has not published a due date.
Enrollment records
1
Earliest due date
Not assigned (TBD)
CMS data updated
2026-06-01
Revalidation progress
- Medicare enrolled
- On CMS revalidation list
- Due date assigned
- Revalidate in PECOS
CMS enrollment records
| Enrollment ID | Type | Specialty | State | Due date |
|---|---|---|---|---|
| I20041108000434 | I | Psychiatry | CA | TBD |
What to do next
- No action required while the due date shows TBD.
- Check the CMS Revalidation Lookup Tool periodically — CMS updates the list about every 60 days.
- Do not submit a revalidation application in PECOS until CMS publishes a concrete due date.
Prepare CMS-855 application → · Look up this NPI in PECOS → · Verify on CMS PECOS
Medicare Utilization (FFS)
Source: CMS public data · Not endorsed by CMS · Beneficiary counts under 11 are suppressed in source data ·
Educational use only—not medical, billing, or legal advice.
Top Medicare procedures (2023) · refreshed 2026-05-27
| HCPCS | Description | Services | Beneficiaries | Medicare allowed |
|---|---|---|---|---|
| 99232 | Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes | 84 | 26 | $0 |
| 99231 | Subsequent hospital care with straightforward or low level of medical decision making, per day, if using time, at least 25 minutes | 56 | 14 | $0 |
| 99233 | Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes | 22 | 11 | $0 |
| 99223 | Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes | 21 | 19 | $0 |
| 99239 | Hospital discharge day management, more than 30 minutes | 17 | 17 | $0 |
Insurance plans in this area (ZIP 94061)
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Group practice members
| Name | Specialty | State |
|---|---|---|
| - | CA | |
| Clinical Psychologist | CA | |
| Internal Medicine | CA | |
| Internal Medicine, Gastroenterology | CA | |
| - | CA | |
| Internal Medicine, Critical Care (Intensivists), Pulmonary Disease | CA | |
| Nurse Practitioner | CA | |
| Internal Medicine, Hospitalist | PA | |
| - | CA | |
| Certified Registered Nurse Anesthetist (Crna) | CA |
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