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DR. EILEEN ANNE O'HALLORAN M.D.
NPI 1447549571
Surgery in Saint Louis, MO

Active since March 29, 2011PECOS EnrolledAccepts Medicare Assignment
607 S NEW BALLAS RD STE 2350, SAINT LOUIS, MO 63141(314) 251-1340 Get Directions Write a Review

NPPES record last updated: August 29, 2024. Verified against the NPPES registry weekly; last sync: October 18, 2026.

About Dr. Eileen Anne O'halloran M.d. NPPES

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

DR. EILEEN ANNE O'HALLORAN M.D. (NPI 1447549571) is an individual surgery provider in Saint Louis, Missouri, licensed in Missouri (2024028245) and active in the NPI registry since March 2011. She is enrolled in Medicare PECOS, is affiliated with Mercy Hospital St Louis, and maintains a secondary practice location in Saint Louis.

NPPES Registry Identity

NPI1447549571
Entity TypeIndividualFemale
Primary Taxonomy208600000X
Provider Legal NameDR. EILEEN ANNE O'HALLORANCredential: M.D.
Location Address607 S NEW BALLAS RD STE 2350Saint Louis, MO 63141-0001
Mailing Address607 S New Ballas Rd Ste 2350Saint Louis, MO 63141-0001 · (314) 251-1340
Phone(314) 251-1340
Sole ProprietorNo
Medical School CMSLoyola University Of Chicago, Stritch School Of MedicineGraduated 2011
Enumeration DateMarch 29, 2011
Last NPPES UpdateAugust 29, 2024
NPPES CertifiedAugust 29, 2024
✔ NPI 1447549571 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtySurgeryAllopathic & Osteopathic Physicians
Taxonomy Code208600000X
Licenses✔ Licensed in MO · 2024028245✔ Licensed in IL · 036.134096
Definition
A general surgeon has expertise related to the diagnosis - preoperative, operative and postoperative management - and management of complications of surgical conditions in the following areas: alimentary tract; abdomen; breast, skin and soft tissue; endocrine system; head and neck surgery; pediatric surgery; surgical critical care; surgical oncology; trauma and burns; and vascular surgery. General surgeons increasingly provide care through the use of minimally invasive and endoscopic techniques. Many general surgeons also possess expertise in transplantation surgery, plastic surgery and cardiothoracic surgery.
607 S NEW BALLAS RD STE 2350, Saint Louis, MO 63141
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Other Names 1

Former Name (1)Eileen Anne Bock Md

Secondary Practice Location 1

Location 110050 Kennerly Rd Ste 2500Saint Louis, MO 63128-2195 · Phone (314) 525-4440

Other Identifiers 2

Other125.060396IL · State Of Illinois Department Of Financial And Professional Regulation
Other036.134096IL · Illinois Department Of Financial And Professional Regulation

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Ambetter from Arkansas Health & Wellness, Ambetter from Sunflower Health Plan, Ambetter Health and more.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

Dr. Eileen Anne O'halloran 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 ID8426359217
PECOS Enrollment IDI20240910001027
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

2

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

Mercy Clinic Surgical Specialists, LLC
32 mi
Vascular Surgery
851 E 5TH ST, SUITE 108
Washington, MO 63090
  • Reassigned Medicare billing, Missouri enrollment
  • 168 clinicians in this Medicare group
NPI 1043530538 (636) 861-7870
Board Of Trustees Of The University Of Illinois
148 mi
Pediatrics
1 ILLINI DR
Peoria, IL 61605
  • Reassigned Medicare billing, Illinois enrollment
  • 2,127 clinicians in this Medicare group
NPI 1467425322 (309) 680-8649

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 2

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.

New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more 99204
This is a first-time office or outpatient visit lasting between 45-59 minutes. The healthcare provider evaluates your health, discusses your medical history, and may suggest further tests or treatments. It's an opportunity to ask questions and understand your health better.
14 services14 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.
13 services12 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 St Louis

Acute Care Hospitals · Saint Louis, MO
4/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number260020
Location615 New Ballas RoadSaint Louis, MO 63141 · St. Louis County
Emergency services Birthing friendly

Mercy Hospital Springfield

Acute Care Hospitals · Springfield, MO
3/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number260065
Location1235 E CherokeeSpringfield, MO 65804 · Greene County
Emergency services Birthing friendly

Mercy Hospital South

Acute Care Hospitals · Saint Louis, MO
3/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number260077
Location10010 Kennerly RoadSaint Louis, MO 63128 · St. Louis County
Emergency services

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 63141 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
$86.32 typical visit price
range $55.65 – $169.38
Typical copayment $21.58 (range $13.91 – $42.34)
Most-billed visit code 99203
Established Patient
$69.50 typical visit price
range $17.76 – $137.92
Typical copayment $17.37 (range $4.44 – $34.48)
Most-billed visit code 99213
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 2

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

ERICA HUELSMANN MD
Obstetrics & Gynecology (Gynecologic Oncology)
607 S NEW BALLAS RD STE 2350
SAINT LOUIS, MO 63141
St. Louis County (314) 251-4260
MRS. REBECCA RUTH SCHNEIDER PA-C
Physician Assistant
607 S NEW BALLAS RD STE 2350
SAINT LOUIS, MO 63141
St. Louis County (314) 251-4260

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Eileen O'halloran's NPI number?

The NPI number for Eileen O'halloran is 1447549571. It was assigned to this individual provider in the NPPES registry on March 29, 2011. The provider is also known as Eileen Anne Bock MD.

Where is Eileen O'halloran located?

Eileen O'halloran practices at 607 S New Ballas Rd Ste 2350, Saint Louis, MO 63141. The listed phone number is (314) 251-1340.

What is Eileen O'halloran's specialty?

The primary specialty registered for this NPI is Surgery with taxonomy code 208600000X.

Is Eileen O'halloran enrolled in Medicare?

Yes. Eileen O'halloran is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organizations bill Medicare for Eileen O'halloran's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Eileen O'halloran reassigns Medicare benefits to 2 organizations: Mercy Clinic Surgical Specialists, LLC (Washington, MO) and Board Of Trustees Of The University Of Illinois (Peoria, IL). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Eileen O'halloran's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does Eileen O'halloran accept?

Health plans from Ambetter Health, Ambetter Health of Delaware, Ambetter from Arkansas Health & Wellness, Ambetter from Sunflower Health Plan and Ambetter of Oklahoma and 3 other insurers list Eileen O'halloran as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

Is Eileen O'halloran affiliated with any hospitals?

According to CMS data, Eileen O'halloran is affiliated with Mercy Hospital St Louis, Mercy Hospital Springfield and Mercy Hospital South.

When was this NPI record last updated?

The NPPES record for Eileen O'halloran was last updated on August 29, 2024. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 years 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.