DR. ROBERT TRISTIAN ISOM (M.D.) – Nephrology Physician, NPI 1356428072
Nephrology Physician
Main info
Doctor Profile
Profile Insights
NPPES metrics only — not quality of care.
60 NEPHROLOGY in ME
Provider Addresses for DR. ROBERT TRISTIAN ISOM (M.D.)
1600 CONGRESS ST STE B
PORTLAND, ME 041022148
Phone:
Type: Mailing
Stanford Hospital, 300, Pasteur Drive, Stanford, Palo Alto, Santa Clara County, California, 94305, United States
STANFORD, CA 943052200
Phone:
Type: Mailing
NPPES updates history
No NPPES updates recorded for this provider.
Prescription Activity
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Open Payments (CMS)
CMS reports 40 Open Payments records for all available years, with a total value of $961.
Total Amount is formed as General ($961) + Research ($0) + Ownership ($0) = $961.
Last reported payment date: 2024-12-17 • Largest payer in this snapshot: Fresenius USA Marketing, Inc. ($252).
Total Amount
$961
General + Research + Ownership
Payments
40
Total payment records
General Amount
$961
General payments
Research Amount
$0
Research funding
Ownership Amount
$0
Ownership interests
Ownership Count
0
Ownership records
Last Payment Date
2024-12-17
Latest reported date
Top Companies
Largest payers in this snapshot
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: 2011-03-24
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 |
|---|---|---|---|---|
| I20110324000661 | I | Nephrology | 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 |
|---|---|---|---|---|
| 36415 | Insertion of needle into vein for collection of blood sample | 96 | 71 | $0 |
| 90960 | Dialysis services, 4 or more physician visits per month (20 years or older) | 88 | 30 | $0 |
| 99204 | New patient office or other outpatient visit, 45-59 minutes | 82 | 82 | $0 |
| 80069 | Kidney function blood test panel | 72 | 58 | $0 |
| 99214 | Established patient office or other outpatient visit, 30-39 minutes | 60 | 47 | $0 |
Insurance plans in this area (ZIP 04102)
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Provider's Procedures
| Specialty | Practice State | HCPCS Code | Description | Service Count | Beneficiary Count |
|---|---|---|---|---|---|
| NEPHROLOGY | CA | 90935 | Hemodialysis procedure with one physician evaluation | 12 | 12 |
Group practice members
| Name | Specialty | State |
|---|---|---|
| N E P H R O L O G Y | CA | |
| Nurse Practitioner | CA | |
| Nurse Practitioner | CA | |
| N E P H R O L O G Y | CA | |
| Nurse Practitioner | CA | |
| N E P H R O L O G Y | CA | |
| N E P H R O L O G Y | CA | |
| N E P H R O L O G Y | MA | |
| N E P H R O L O G Y | CA |
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