Colonoscopy clinicians in Madison, Wisconsin

CMS lists 42 clinicians with a primary specialty of Gastroenterology, Internal Medicine, Family Practice, or General Practice who have billed Medicare for at least one colonoscopy and practice in Madison, Wisconsin (details below).

Colonoscopy volume

Clinician	Colonoscopies billed	Percentile rank
Michael Allan, MD	202	89%
Jason Gonzaga, MD	191	87%
Geoffrey Dang-Vu, MD	190	87%
Antonio Bosch, MD	176	85%
Alexander Lee, MD	172	84%
Abby Lochmann-Bailkey, MD	170	84%
Alexander Larson, MD	158	82%
John Williams, MD	155	81%
Andrew Walker, MD	131	75%
Naree Whang, MD	130	74%
Siobhan Byrne, MD	115	69%
Anurag Soni, MD	112	68%
Peter Stadmeyer, MD	112	68%
Patrick Pfau, MD	102	65%
Bryan Magenheim, MD	97	63%
Kevin Patel, MD	94	62%
Rodrigo Castillo, MD	89	59%
Freddy Caldera, DO	75	52%
Peter Stanko, MD	75	52%
Sumona Saha, MD	68	49%
Andrew Spiel, MD	66	48%
Christopher Lindholm, MD	62	46%
Megan Lutz, MD	60	45%
Eric Gaumnitz, MD	57	43%
Kerstin Austin, MD	56	42%
Ian Grimes, MD	56	42%
Mark Benson, MD	48	38%
Deepak Gopal, MD	44	35%
Margarita German, MD	41	33%
Derek Hubbard, MD	41	33%
Luis Lomeli, MD	37	31%
Praveena Narayanan, MD	22	21%
Adnan Said, MD	22	21%
Jennifer Weiss, MD	21	20%
Lisa Strate, MD	20	19%
Gabriela Lobato, MD	18	18%
Vinay Patel, MD	18	18%
Mansoor Shariff, MD	17	17%
Gary Griglione, MD	13	15%
Nicole Boschuetz, MD	12	14%
Anne Kolan, MD	1-10	13% or below
Jessica Musto, MD	1-10	13% or below

Sorted by the number of colonoscopies billed to Medicare, highest first, not by quality or skill. CMS suppresses counts between 1 and 10 to protect patient privacy and publishes the range instead.

Understanding CMS Data

CMS's "Colonoscopy" category combines specific billing codes for colonoscopy to calculate the number of times each clinician billed Medicare for a "Colonoscopy." These include screening colonoscopy, diagnostic colonoscopy, and colonoscopy with biopsy or polyp removal. CMS's list also includes flexible sigmoidoscopy and laparoscopic appendectomy, so a clinician's count may include those procedures. CMS counts one procedure per patient per day, so a colonoscopy that included both a biopsy and a polyp removal counts once. CMS reports only procedures that clinicians billed to Original Medicare and Medicare Advantage. Therefore, CMS's procedure volume data does not include procedures that clinicians may have performed on patients who have other health care coverage (e.g., commercial insurance, self-pay, or the VA). Billing variation and coding errors can also affect CMS's data. Therefore, the number of procedures that CMS reports for a clinician may be higher or lower than the actual number of colonoscopies a clinician performed during the reporting period. Lastly, only clinicians with a primary specialty of Gastroenterology, Internal Medicine, Family Practice, or General Practice (as reported to Medicare) are presented.

Source: Centers for Medicare & Medicaid Services (August 18, 2026 release).