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Compare the published Medicare service mix of Joseph H Chammas, M.D. with clinicians in the same registry specialty: Cardiovascular Disease (Cardiology) · Thoracic Surgery (CMS).

SAN DIEGO, CA · Exact areaEdit location

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

Seemal Mumtaz, M.D.

General Surgery · Thoracic Surgery (CMS) · San Diego, CA

Shared published services
2 shared services · view billing descriptions
  • Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes (99232)
  • Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes (99222)
42%Service-mix similarityView profile →

James R. Hemp, M.D.

Cardiac Surgery · General Surgery · Thoracic Surgery · Vascular Surgery (CMS) · San Diego, CA

Shared published services
2 shared services · view billing descriptions
  • Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more (99212)
  • Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes (99222)
24%Service-mix similarityView profile →

Ara S. Klijian, M.D.

Cardiac Surgery · Thoracic Surgery (CMS) · San Diego, CA

Shared published services
1 shared services · view billing descriptions
  • Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes (99232)
22%Service-mix similarityView profile →

Gert Diederick Victor Pretorius, MD

Cardiac Surgery · General Surgery · Thoracic Surgery (CMS) · San Diego, CA

Shared published services
1 shared services · view billing descriptions
  • Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes (99222)
19%Service-mix similarityView profile →

Daniel Lawrence Gramins, M.D.

Cardiac Surgery (CMS) · San Diego, CA

Shared published services
1 shared services · view billing descriptions
  • Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes (99222)
18%Service-mix similarityView profile →

Mark Bergida Mitchell, MD

Thoracic Surgery (CMS) · San Diego, CA

Shared published services
1 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)
18%Service-mix similarityView profile →

Mark William Onaitis, MD

Thoracic Surgery (CMS) · San Diego, CA

Shared published services
1 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)
17%Service-mix similarityView profile →

Joshua August Boys, M.D.

Thoracic Surgery (CMS) · San Diego, CA

Shared published services
1 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)
15%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.