CHOON SIL KOO (M.D.) – Anatomic Pathology & Clinical Pathology Physician, NPI 1265427595
Anatomic Pathology & Clinical Pathology Physician
Main info
Doctor Profile
Profile Insights
NPPES metrics only — not quality of care.
1,584 PATHOLOGY in CA
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Provider Addresses for CHOON SIL KOO (M.D.)
Chatsworth Post Office, Devonshire Street, Chatsworth Neighborhood Council District, Los Angeles, Los Angeles County, California, 91311, United States
CHATSWORTH, CA 913132311
Phone: (818) 718-9500
Fax: (818) 718-9507
Type: Mailing
San Antonio Regional Hospital, 999, San Bernardino Road, Upland, San Bernardino County, California, 91786, United States
UPLAND, CA 917864920
Phone: (909) 985-2811
Fax: (909) 920-3827
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.
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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: 2009-08-14
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 |
|---|---|---|---|---|
| I20090814000611 | I | Pathology | 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 |
|---|---|---|---|---|
| 88305 | Pathology examination of tissue using a microscope, intermediate complexity | 550 | 352 | $0 |
| 88341 | Special stained specimen slides to examine tissue, each additional procedure | 244 | 62 | $0 |
| 88342 | Special stained specimen slides to examine tissue, initial procedure | 184 | 157 | $0 |
| 88313 | Special stained specimen slides to examine tissue including interpretation and report | 115 | 49 | $0 |
| 88307 | Pathology examination of tissue using a microscope, moderately high complexity | 107 | 65 | $0 |
Insurance plans in this area (ZIP 91313)
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Provider's Procedures
Group practice members
| Name | Specialty | State |
|---|---|---|
| P A T H O L O G Y | CA |
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