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Compare the published Medicare service mix of Robert Tristian Isom, M.D. with clinicians in the same registry specialty: Nephrology (CMS).

PORTLAND, ME · Exact areaEdit location

2024 published service data · 19 eligible profiles compared. Similarity describes billing patterns, not quality, outcomes, or suitability for your care.

Eric N Taylor, MD

Internal Medicine · Nephrology (CMS) · Portland, ME

Shared published services
2 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
43%Service-mix similarityView profile →

John Patrick Vella, M.D.

Internal Medicine · Nephrology (CMS) · Portland, ME

Shared published services
3 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
  • Complete ultrasound scan behind abdominal cavity (76770)
42%Service-mix similarityView profile →

Hassan Mahmoud, M.D.

Nephrology (CMS) · Portland, ME

Shared published services
3 shared services · view billing descriptions
  • Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
40%Service-mix similarityView profile →

Sean Andrew Hebert, MD

Nephrology (CMS) · Portland, ME

Shared published services
3 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)
  • Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes (99232)
36%Service-mix similarityView profile →

Grant Oakley, D.O.

Nephrology (CMS) · Portland, ME

Shared published services
3 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
  • Dialysis services, 4 or more physician visits per month (20 years or older) (90960)
35%Service-mix similarityView profile →

Abd Assalam Qannus, M.D.

Nephrology (CMS) · Portland, ME

Shared published services
3 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)
  • Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes (99232)
35%Service-mix similarityView profile →

Michael Christopher Akom, M.D.

Internal Medicine · Nephrology (CMS) · Portland, ME

Shared published services
3 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • Complete ultrasound scan behind abdominal cavity (76770)
  • Dialysis services, 4 or more physician visits per month (20 years or older) (90960)
34%Service-mix similarityView profile →

Mark Godfrey Parker, M.D.

Internal Medicine · Nephrology (CMS) · Portland, ME

Shared published services
2 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • Complete ultrasound scan behind abdominal cavity (76770)
33%Service-mix similarityView profile →

Gary Diperna, DO

Internal Medicine · Nephrology (CMS) · Portland, ME

Shared published services
3 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • Dialysis services, 4 or more physician visits per month (20 years or older) (90960)
  • Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes (99232)
30%Service-mix similarityView profile →

Ioan Cosma, MD

Internal Medicine · Nephrology (CMS) · Portland, ME

Shared published services
3 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • Complete ultrasound scan behind abdominal cavity (76770)
  • Dialysis services, 4 or more physician visits per month (20 years or older) (90960)
27%Service-mix similarityView profile →

Stepfany Fuentes, DO

Internal Medicine · Nephrology (CMS) · Portland, ME

Shared published services
2 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
26%Service-mix similarityView profile →

Eric Holmes, PA-C

Physician Assistant (CMS) · Portland, ME

Shared published services
1 shared services · view billing descriptions
  • Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)
25%Service-mix similarityView profile →
How this comparison works

We use the same calendar year of CMS Medicare Physician & Other Practitioners data for both providers. Published non-drug service counts are combined by HCPCS code across places of service. We apply log(1 + count), normalize the vectors, and compare them using cosine similarity.

Candidates share the reference provider’s current NPPES primary taxonomy and match the location you enter. We examine up to 500 candidates in NPI order, then show up to 12 with the highest positive similarity within that set. The score is not a percentile, medical recommendation, or prediction. Suppressed services are not estimated. Medicare fee-for-service data does not describe a provider’s entire practice.

Source: CMS Medicare Physician & Other Practitioners - by Provider and Service : 2024-12-01 · Published May 21, 2026.