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Compare the published Medicare service mix of John O'brien Clarke, M.D. with clinicians in the same registry specialty: Gastroenterology (CMS).

PALO ALTO, CA · Exact areaEdit location

2024 published service data · 14 eligible profiles compared. Similarity describes billing patterns, not quality, outcomes, or suitability for your care.

Irene Seungwan Sonu, MD

Gastroenterology · Internal Medicine (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • Measurement of hydrogen in breath to test for stomach and bowel symptoms (91065)
80%Service-mix similarityView profile →

Patricia Adriana Garcia, M.D.

Gastroenterology (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • Measurement of hydrogen in breath to test for stomach and bowel symptoms (91065)
75%Service-mix similarityView profile →

Nielsen Quimaira Fernandez-Becker, M.D., PH.D.

Gastroenterology · Internal Medicine (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • Measurement of hydrogen in breath to test for stomach and bowel symptoms (91065)
69%Service-mix similarityView profile →

Sundeep Singh, M.D.

Gastroenterology · Internal Medicine (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
62%Service-mix similarityView profile →

Aarti Kallianpur Rao, MD

Gastroenterology (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
57%Service-mix similarityView profile →

Chiazotam Nkemdilim Ekekezie, M.D.

Gastroenterology · Internal Medicine (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
55%Service-mix similarityView profile →

Erick Peiren Chan, MD

Gastroenterology (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
55%Service-mix similarityView profile →

Susie M Liu, MD

Gastroenterology · Internal Medicine (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
54%Service-mix similarityView profile →

Brennan Scott, MD

Gastroenterology (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
54%Service-mix similarityView profile →

Andrew Kees Roorda, M.D.

Gastroenterology · Internal Medicine (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
52%Service-mix similarityView profile →

Chelsea Xu

Gastroenterology (CMS) · Palo Alto, CA

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)
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)
49%Service-mix similarityView profile →

Ryan Arthur Mcconnell, MD

Gastroenterology (CMS) · Palo Alto, CA

Shared published services
3 shared services · view billing descriptions
  • Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)
  • Visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient's (G2211)
  • Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)
49%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.