Robert Tristian Isom, M.D.
Nephrology Physician · Portland, ME
Robert Tristian Isom, M.D. is a nephrology physician with a practice address in Portland, Maine, and NPI 1356428072, issued on Nov 1, 2006. Check the license (Maine MD25822, as entered in NPPES) on the Maine Board of Licensure in Medicine; the Medicare figures below come from public CMS files.
- Name
- Robert Tristian Isom
- Credential
- M.D.
- Primary taxonomy
- Nephrology Physician 207RN0300X
- License numbers
- MD25822 ME
217627 NY
Self-reported in NPPES; status is on the state search - Practice location
- 1600 Congress St Ste B, Portland, ME 04102
- Phone
- (207) 774-5222
- Enumerated
- Nov 1, 2006
- Record last updated
- May 24, 2022
- Medicaid ID
- 02423449 NY
- Medicare enrollment
- Enrolled (PECOS I20110324000661); accepts Medicare assignment
- Medical or professional school
- Columbia University College Of Physicians And Surgeons, 1997
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest nephrology physician records → All 50 in Maine → Look up another NPI →
Also registered at 1600 Congress St Ste B
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Zain Alshanableh, MDNephrology Physician1972159598
- Jonathan Amatruda, M.D.Nephrology Physician1912387713
- Lola Amdahl, PA-CPhysician Assistant1487291050
- Melissa Asci, APRN-CNPAcute Care Nurse Practitioner1881483030
- Abigail Cleary, AGACNPAcute Care Nurse Practitioner1811795008
- Robert Hayden, MDNephrology Physician1912468778
Verify Robert Tristian Isom in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMaine Board of Licensure in Medicine
Search for license MD25822Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
3% more Medicare Part D claims than the average nephrology physician in 2024
1,509 Medicare Part D claims for 233 beneficiaries, against an average of 1,465 among the 10,986 providers of this specialty who prescribed in Part D. Brand-name drugs were 20% of claims.
Most prescribed
- Amlodipine Besylate158 claims
- Jardiance158 claims
- Calcitriol99 claims
- Losartan Potassium73 claims
- Famotidine59 claims
- Chlorthalidone57 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Industry payments in 2024: $854.26
35 payments; by number, the most common kind was food and beverage; the largest payer was Fresenius USA Marketing, Inc. The 8,230 providers of this specialty with any payment received $3,091.37 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Central Coast Nephrology Medical CorporationSalinas, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Robert Tristian Isom among 50 nephrology physician records in Maine
Robert Tristian Isom, M.D. is one of 50 nephrology physician records with a practice address in Maine. 86% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 28% of them.
- NPI issued2006 · 28% of these records are older, 46% newer
- In a Medicare fileYes · 86% of these records are
- In the CMS Doctors and Clinicians fileYes · 76% of these records are
- Graduated1997 · median 2001 among the 38 with a school on file
- Record last updated2022 · 64% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RN0300X and a Maine practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Nephrology Physician providers in Maine
There are 50 nephrology physician records in Maine.
All 50 in Maine → Every provider in Portland → Nephrology Physician nationwide →
The 8 nephrology physician records with the nearest ZIP codes
- Michael Akom, M.D.Portland, ME 041021508827585
- Carl Blond, M.D.Portland, ME 041021174507776
- Patricia Cantlin, DOPortland, ME 041021275533994
- Ioan Cosma, MDPortland, ME 041021356540454
- Gary Diperna, DOPortland, ME 041021649567579
- Mahendra Mangray, MDPortland, ME 041021801074919
- Paul Parker, MDPortland, ME 041021649278029
- Mark Parker, M.D.Portland, ME 041021770583346
Common questions
What is Robert Tristian Isom, M.D.'s NPI number?
Robert Tristian Isom, M.D.'s National Provider Identifier (NPI) is 1356428072, issued on Nov 1, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Robert Tristian Isom, M.D. located?
The NPPES record lists a practice address at 1600 Congress St Ste B, Portland, ME, 04102. Phone: (207) 774-5222. Providers update this record themselves, so call before visiting.
How can I verify Robert Tristian Isom, M.D.'s license?
NPPES lists Maine license number MD25822, as entered by the provider. Search the Maine Board of Licensure in Medicine at https://www.maine.gov/md/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Robert Tristian Isom, M.D. prescribe under Medicare Part D?
In 2024, Robert Tristian Isom, M.D. had 1,509 Medicare Part D claims for 233 beneficiaries; the average among nephrology physician prescribers was 1,465. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.