DR. MARGARET K WILLIAMSON MD
NPI 1154514867
Emergency Medicine in Oak Lawn, IL

Q: What is Margaret Williamson's NPI number?

The NPI number for Margaret Williamson is 1154514867. It was assigned to this individual provider in the NPPES registry on August 26, 2007.

Q: What is Margaret Williamson's specialty?

The primary specialty registered for this NPI is Emergency Medicine with taxonomy code 207P00000X.

Active since August 26, 2007PECOS EnrolledAccepts Medicare Assignment

4440 W 95TH ST, OAK LAWN, IL 60453(434) 466-2969 Get Directions Write a Review

NPPES record last updated: March 12, 2024. Verified against the NPPES registry weekly; last sync: August 09, 2026.

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About Dr. Margaret K Williamson Md NPPES

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

DR. MARGARET K WILLIAMSON MD (NPI 1154514867) is an individual emergency medicine provider in Oak Lawn, Illinois, licensed in Illinois (036126342) and active in the NPI registry since August 2007. She is enrolled in Medicare PECOS, is affiliated with Northwestern Memorial Hospital, and maintains a secondary practice location in Chicago.

NPPES Registry Identity

NPI1154514867

Entity TypeIndividualFemale

Primary Taxonomy207P00000X

Provider Legal NameDR. MARGARET K WILLIAMSONCredential: MD

Location Address4440 W 95TH STOak Lawn, IL 60453-2600

Mailing Address29373 Network PlChicago, IL 60673-1293 · (847) 390-5900

Phone(434) 466-2969

Sole ProprietorNo

Medical School CMSUniversity Of Virginia School Of MedicineGraduated 2007

Enumeration DateAugust 26, 2007

Last NPPES UpdateMarch 12, 2024

NPPES CertifiedMarch 12, 2024

✔ NPI 1154514867 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyEmergency MedicineAllopathic & Osteopathic Physicians

Taxonomy Code207P00000X

Licenses✔ Licensed in IL · 036126342✔ Licensed in IL · 125-052545

Definition

An emergency physician focuses on the immediate decision making and action necessary to prevent death or any further disability both in the pre-hospital setting by directing emergency medical technicians and in the emergency department. The emergency physician provides immediate recognition, evaluation, care, stabilization and disposition of a generally diversified population of adult and pediatric patients in response to acute illness and injury.

4440 W 95TH ST, Oak Lawn, IL 60453

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Secondary Practice Location 1

Location 1211 E Ontario St Ste 200Chicago, IL 60611-3284 · Phone (312) 694-7000 · Fax (312) 926-6274

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, and ordering and referring status from the CMS PECOS system.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Margaret K Williamson Md 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 ID446420384

PECOS Enrollment IDI20110831000604

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.

Areas of Expertise CMS Part B claims 5

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.

Emergency department visit with high level of medical decision making 99285

An emergency department visit for severe conditions is when you urgently seek medical help due to serious health issues. These could be severe injuries, breathing problems, unbearable pain, or sudden severe illness. Doctors and nurses will provide immediate care to stabilize your condition.

259 services255 patients

Emergency department visit with moderate level of medical decision making 99284

An emergency department visit for a high-severity issue means you're experiencing a serious health problem that needs immediate attention. This could be a severe injury, serious illness, or life-threatening condition. Medical professionals will provide urgent care to stabilize your condition.

118 services116 patients

Critical care, first 30-74 minutes 99291

Critical care involves immediate and constant attention by a team of specially-trained health professionals. It's for patients with life-threatening conditions, requiring first 30-74 minutes of intense monitoring and treatment.

31 services30 patients

Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 99223

Initial hospital inpatient care per day, typically 70 minutes, refers to the daily medical service provided to patients admitted to the hospital. This includes a comprehensive evaluation, diagnosis, treatment plan, and monitoring of your health condition. It ensures your well-being during your hospital stay.

19 services19 patients

Emergency department visit with low level of medical decision making 99283

An emergency department visit for a problem of moderate severity involves immediate medical attention for issues like minor fractures, burns, or high fever. The healthcare team will assess your condition, provide necessary treatment, and may suggest further tests or admission if required.

19 services17 patients

Hospital Affiliations CMS Care Compare

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

Northwestern Memorial Hospital

Acute Care Hospitals · Chicago, IL

5/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number140281

Location251 E Huron StChicago, IL 60611 · Cook County

Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 60453 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

$94.06 typical visit price

range $60.08 – $183.39

Typical copayment $23.51 (range $15.02 – $45.84)

Most-billed visit code 99203

Established Patient

$105.70 typical visit price

range $18.97 – $148.12

Typical copayment $26.42 (range $4.74 – $37.03)

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.

Other Providers at the Same Location NPPES 20

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

DR. MARK ADRIAN FAASSE MD

Urology