Barbara Obrien, MD

As reported to Medicare

Credential: MD
Primary specialty: Gastroenterology
Medical school graduation: 1992
National Provider Identifier (NPI): 1821097304

Practice location

Source: Centers for Medicare & Medicaid Services

# of Colonoscopies Billed to Medicare

1-10

Total number of colonoscopies this clinician billed to Medicare in the most recent 12-month claims period, according to CMS.

Why is it showing a range? To protect patient privacy, CMS reports a "1-10" range for the number of procedures when a clinician bills Medicare only one to ten times for qualifying procedures.

Percentile Rank (%)

13% or below

A range of 1-10 procedures places a clinician at or below the 13th percentile.

The figures above reflect only procedures that this clinician billed to Medicare, according to CMS. Therefore, they may not reflect the total number of procedures this clinician performed during the 12-month reporting period. See Understanding CMS Data below.

Source: Centers for Medicare & Medicaid Services (October 2, 2026 release).

Barbara Obrien's Colonoscopy Billing Volume Compared to Peers

CMS reports this clinician's count as a range rather than an exact number, so no single point can be marked. Every clinician CMS reports as 1-10 sits below every clinician with an exact count above that range, which puts them at or below the 13th percentile: the highlighted block. The shaded block covers the 2,202 clinicians CMS reports as 1-10, because CMS suppresses counts below 11.

Source: Centers for Medicare & Medicaid Services (October 2, 2026 release).

Colonoscopies billed to Medicare at each tenth percentile of clinicians with a primary specialty of Gastroenterology, Internal Medicine, Family Practice, or General Practice. This clinician: CMS reports a range, so they sit at or below the 13th percentile.
Percentile	Colonoscopies billed to Medicare
20th	21
30th	37
40th	52
50th	70
60th	90
70th	116
80th	150
90th	209
Highest	1,538

Previous data releases

The table shows this clinician's figures from each CMS data release.

CMS data release	Colonoscopies billed	Percentile rank
October 2, 2026 Current	1-10	13% or below
August 18, 2026 Prior	1-10	13% or below
August 11, 2026 Prior	1-10	13% or below
June 26, 2026 Prior	1-10	15% or below

CMS does not publish the start and end dates of the window behind any release, and consecutive releases may cover overlapping periods, or the same period with later-arriving claims added.

Understanding CMS Data

This count includes 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 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.

We use CMS's percentile formula with a narrower comparison group than CMS's own, so our percentile can differ from the one CMS publishes.

How CMS counts colonoscopies, and how we calculate the percentile