GARY DAVID KOENIG M.D.
NPI 1861485724
Internal Medicine - Gastroenterology in Hazelwood, MO

Q: What is Gary Koenig's NPI number?

The NPI number for Gary Koenig is 1861485724. It was assigned to this individual provider in the NPPES registry on August 25, 2005.

Q: What is Gary Koenig's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Gastroenterology, with taxonomy code 207RG0100X.

Q: When was this NPI record last updated?

The NPPES record for Gary Koenig was last updated on February 16, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 8 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.

Active since August 25, 2005PECOS EnrolledAccepts Medicare Assignment

62.28/100

CMS Quality Rating

100 VILLAGE SQ, HAZELWOOD, MO 63042(314) 355-4010(314) 355-9484 Get Directions Write a Review

NPPES record last updated: February 16, 2026. Verified against the NPPES registry weekly; last sync: October 18, 2026.

On this page

About Gary David Koenig M.d. NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

GARY DAVID KOENIG M.D. (NPI 1861485724) is an individual gastroenterology provider in Hazelwood, Missouri, licensed in Missouri (MDR3G44) and active in the NPI registry since August 2005. He is enrolled in Medicare PECOS, is affiliated with Mercy Hospital Washington, and maintains a secondary practice location in O Fallon.

NPPES Registry Identity

NPI1861485724

Entity TypeIndividualMale

Primary Taxonomy207RG0100X

Provider Legal NameGARY DAVID KOENIGCredential: M.D.

Location Address100 VILLAGE SQHazelwood, MO 63042-1820

Mailing AddressPo Box 23340Saint Louis, MO 63156-3340 · (314) 355-4010 · Fax (314) 355-9484

Phone(314) 355-4010

Fax(314) 355-9484

Sole ProprietorYes

Medical School CMSSaint Louis University School Of MedicineGraduated 1986

Enumeration DateAugust 25, 2005

Last NPPES UpdateFebruary 16, 2026

NPPES CertifiedFebruary 16, 2026

✔ NPI 1861485724 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal Medicine · GastroenterologyAllopathic & Osteopathic Physicians

Taxonomy Code207RG0100X

Licenses✔ Licensed in MO · MDR3G44✔ Licensed in MO · RG344

Definition

An internist who specializes in diagnosis and treatment of diseases of the digestive organs including the stomach, bowels, liver and gallbladder. This specialist treats conditions such as abdominal pain, ulcers, diarrhea, cancer and jaundice and performs complex diagnostic and therapeutic procedures using endoscopes to visualize internal organs.

100 VILLAGE SQ, Hazelwood, MO 63042

Open in Google Maps ↗

Secondary Practice Location 1

Location 120 Progress Point Pkwy Ste 206O Fallon, MO 63368-2207 · Phone (636) 344-1073 · Fax (636) 916-9953

Other Identifiers 1

Medicaid202823316MO

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Anthem Blue Cross and Blue Shield, Florida Blue (BlueCross BlueShield FL), Florida Blue HMO (a BlueCross BlueShield FL company).Insurance ›

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Gary David Koenig M.d. is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID9335169887

PECOS Enrollment IDI20090803000025

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignments

Medicare enrollment records show Gary Koenig reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Mercy Clinic Gastroenterology, LLC

2.6 mi

Gastroenterology

621 S NEW BALLAS RD, SUITE 437-A
Saint Louis, MO 63141

Reassigned Medicare billing, Missouri enrollment
69 clinicians in this Medicare group

NPI 1528295334 (314) 251-3880

Physician Groups Lc

3.7 mi

Multi-Specialty

670 MASON RIDGE CENTER DR STE 300
Saint Louis, MO 63141

Reassigned Medicare billing, Missouri enrollment
611 clinicians in this Medicare group

NPI 1285664268 (314) 996-7644

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Areas of Expertise CMS Part B claims 12

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes 99222

Initial hospital inpatient care is a service where a healthcare provider spends about 50 minutes per day overseeing your care while you're admitted in the hospital. This includes reviewing your health status, planning your treatment, and ensuring your safety and comfort.

46 services44 patients

Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope 43239

This procedure involves using a thin, flexible tube with a light and camera, known as an endoscope, to examine the esophagus, stomach, and upper part of the small intestine. Small tissue samples are taken for further examination to help diagnose various conditions.

45 services45 patients

Removal of polyps or growths of large bowel using an endoscope with mechanical snare 45385

This procedure involves using a thin, flexible tube called an endoscope to examine the large bowel. If any abnormal growths or polyps are found, a tool called a mechanical snare is used to remove them. This is a common method to prevent potential health issues.

36 services36 patients

Colorectal cancer screening; colonoscopy on individual not meeting criteria for high risk G0121

Colorectal cancer screening, such as a colonoscopy, is a preventive measure to detect early signs of cancer in the large intestine. For individuals not at high risk, it's typically recommended at age 50. A small, flexible tube with a camera is used to examine your colon. It's a safe, effective way to catch issues early.

34 services34 patients

Biopsy of large bowel using a flexible endoscope 45380

A biopsy of the large bowel using a flexible endoscope is a procedure where a thin, flexible tube with a camera is inserted through the rectum to examine the bowel. If abnormal tissue is found, a small sample is taken for further examination. This helps in diagnosing conditions like inflammation, polyps, or cancer.

32 services32 patients

Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 99232

Follow-up hospital inpatient care involves daily check-ups while you're admitted in the hospital. Typically, a healthcare provider spends about 25 minutes each day reviewing your condition, adjusting treatment if needed, and answering any questions you might have.

24 services18 patients

Colorectal cancer screening; colonoscopy on individual at high risk G0105

Colorectal cancer screening, specifically a colonoscopy, is a preventive measure for those at high risk. A thin, flexible tube with a camera inspects the colon to spot any abnormal growths. This test helps detect potential issues early, enhancing the effectiveness of treatment.

24 services24 patients

New patient office or other outpatient visit with low level of medical decision making, if using time, 30 minutes or more 99203

This service involves an initial office or outpatient visit for a new patient. The healthcare professional will spend 30-44 minutes understanding your health history, current issues, and discussing possible treatment plans. It's a comprehensive evaluation to start your healthcare journey.

21 services21 patients

Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more 99213

This is a routine visit for patients who have already been seen by the healthcare provider. During this approximately 20-29 minute appointment, your health status will be evaluated and any necessary treatments or tests will be discussed. It's a chance to address any health concerns you may have.

18 services17 patients

Diagnostic exam of esophagus, stomach, and/or upper small bowel using a flexible endoscope 43235

This procedure, known as an upper endoscopy, involves inserting a thin, flexible tube with a camera down the throat to examine the esophagus, stomach, and upper small bowel. It helps diagnose conditions like ulcers or inflammation.

16 services16 patients

Diagnostic exam of large bowel using a flexible endoscope 45378

This procedure, known as a colonoscopy, involves using a flexible tube with a light and camera to examine the large intestine. It helps detect any abnormalities such as polyps or inflammation. It's a standard procedure to ensure gut health.

12 services12 patients

Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more 99214

This is a routine check-up for patients who have previously visited our clinic. It involves a comprehensive review of your health and any ongoing treatments. The consultation lasts between 30-39 minutes, allowing enough time to discuss any concerns.

11 services11 patients

Hospital Affiliations CMS Care Compare 3

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

Mercy Hospital Washington

Acute Care Hospitals · Washington, MO

4/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number260052

Location901 East 5th StreetWashington, MO 63090 · Franklin County

Emergency services

Barnes-Jewish St Peters Hospital

Acute Care Hospitals · Saint Peters, MO

5/5 CMS rating

OwnershipVoluntary non-profit - Other

CMS Certification Number260191

Location10 Hospital DrSaint Peters, MO 63376 · St. Charles County

Emergency services

Progress West Hospital

Acute Care Hospitals · O Fallon, MO

4/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number260219

Location2 Progress Point PkwyO Fallon, MO 63368 · St. Charles County

Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 63042 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient

$128.28 typical visit price

range $55.65 – $169.38

Typical copayment $32.07 (range $13.91 – $42.34)

Most-billed visit code 99204

Established Patient

$98.37 typical visit price

range $17.76 – $137.92

Typical copayment $24.59 (range $4.44 – $34.48)

Most-billed visit code 99214

Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Medicare Quality Performance CMS QPP · MIPS

Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.

62.28/100

MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program

Scored as part of a group practice

Quality

19.39

Promoting Interoperability

Improvement Activities

Cost

69.88

Other Providers at the Same Location NPPES 9

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

DREAMLAND UAP ANESTHESIA, LLC

Nurse Anesthetist, Certified Registered