DR. GERALDINE GAN TAN (MD) – Hospitalist Physician, NPI 1699744086
Hospitalist Physician
Main info
Doctor Profile
Profile Insights
NPPES metrics only — not quality of care.
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Provider Addresses for DR. GERALDINE GAN TAN (MD)
San Francisco, Province of Ambo, Huánuco, Peru
P.O. BOX 39000
SAN FRANCISCO, CA 941390001
Phone: (925) 952-2828
Fax: (925) 952-2850
Type: Mailing
1220, Rossmoor Parkway, Walnut Creek, Contra Costa County, California, 94595, United States
WALNUT CREEK, CA 945952501
Phone: (925) 947-3393
Fax: (925) 947-3396
Type: Location
NPPES updates history
No NPPES updates recorded for this provider.
Prescription Activity
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Open Payments (CMS)
No Open Payments data available for this provider.
This can happen when there are no reportable CMS Open Payments records.
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: 2004-09-28
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 |
|---|---|---|---|---|
| I20040928000701 | I | Internal Medicine | 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.
No Medicare fee-for-service utilization data available for this provider in our database.
Insurance plans in this area (ZIP 94139)
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Group practice members
| Name | Specialty | State |
|---|---|---|
| Diagnostic Radiology, Nuclear Medicine | CA | |
| Internal Medicine, Geriatric Medicine | CA | |
| Diagnostic Radiology | CA | |
| Diagnostic Radiology, Interventional Radiology, Diagnostic Radiology | CA | |
| Diagnostic Radiology | CA | |
| Diagnostic Radiology, Pediatric Medicine | CA | |
| Diagnostic Radiology | CA | |
| N E U R O S U R G E R Y | CA | |
| Diagnostic Radiology | CA | |
| Diagnostic Radiology | CA |
Reviews
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