Colonoscopy clinicians in Lexington, Kentucky

CMS lists 38 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 Lexington, Kentucky (details below).

Colonoscopy volume

Clinician	Colonoscopies billed	Percentile rank
An-Yu Chen, MD	169	84%
Matthew Ashmun, MD	145	79%
Todd Horn, MD	140	77%
Adalberto Castellanos, MD	125	73%
Stephen Schindler, MD	124	73%
June Yong, MD	119	71%
James Pezzi, MD	112	69%
Nathan Massey, MD	107	67%
Kathleen Martin, MD	91	60%
Gregory Woolfolk, MD	82	56%
John Brown, MD	80	55%
Scott Merkley	76	53%
Warren Frank, MD	74	52%
Deborah Flomenhoft, MD	53	40%
Mark Brunner, MD	51	39%
Damir Kusmic, MD	47	36%
Courtney Perry, DO	47	36%
Victor Howard	40	32%
Terrence Barrett, MD	35	28%
Brooks Richardson, MD	33	27%
Marijeta Pekez, MD	31	26%
Venkata Rajesh Konjeti, MD	30	25%
Ruben Plentz, MD	30	25%
Bahaaeldeen Ismail, MD	28	24%
Jens Rosenau, MD	27	23%
Joseph Auer	26	23%
Donald Campbell, MD	25	22%
Christina Leyson, MD	15	16%
Donald Rauh, MD	15	16%
Ujasbhai Patel, MD	12	14%
Kshitij Thakur, MD	12	14%
Nishant Tripathi, MD	12	14%
Steven Shedlofsky, MD	11	13%
Ingrid Beyruth Schwartz, MD	1-10	13% or below
Lanla Conteh, MD	1-10	13% or below
Darwin Conwell, MD	1-10	13% or below
Alla Grigorian, MD	1-10	13% or below
Samuel Mardini, 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.

Reported in previous releases

CMS does not report a colonoscopy volume for these clinicians in the October 2, 2026 release. Their pages show figures from earlier releases.

Laurie Haas, MD Last reported August 18, 2026
Mark Spurlin, MD Last reported August 18, 2026

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 (October 2, 2026 release).