WILLIAM T LESLIE M.D.
NPI 1538129275
Internal Medicine - Hematology & Oncology in Chicago, IL

Q: What is William Leslie's NPI number?

The NPI number for William Leslie is 1538129275. It was assigned to this individual provider in the NPPES registry on March 25, 2006.

Q: What is William Leslie's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Hematology & Oncology, with taxonomy code 207RH0003X.

Q: When was this NPI record last updated?

The NPPES record for William Leslie was last updated on April 14, 2011. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 15 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.

Active since March 25, 2006PECOS EnrolledAccepts Medicare Assignment

1725 W HARRISON ST, SUITE 1010, CHICAGO, IL 60612(312) 942-5904 Get Directions Write a Review

NPPES record last updated: April 14, 2011. Verified against the NPPES registry weekly; last sync: November 08, 2026.

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About William T Leslie M.d. NPPES

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

WILLIAM T LESLIE M.D. (NPI 1538129275) is an individual hematology & oncology provider in Chicago, Illinois, licensed in Illinois (036-058921) and active in the NPI registry since March 2006. He is enrolled in Medicare PECOS, is affiliated with Rush Oak Park Hospital, and is a graduate of Other (1978).

NPPES Registry Identity

NPI1538129275

Entity TypeIndividualMale

Primary Taxonomy207RH0003X

Provider Legal NameWILLIAM T LESLIECredential: M.D.

Location Address1725 W HARRISON ST, SUITE 1010Chicago, IL 60612-3841

Mailing Address1725 W Harrison St, Suite 1010Chicago, IL 60612-3841 · (312) 942-5904

Phone(312) 942-5904

Sole ProprietorNo

Medical School CMSOtherGraduated 1978

Enumeration DateMarch 25, 2006

Last NPPES UpdateApril 14, 2011

✔ NPI 1538129275 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal Medicine · Hematology & OncologyAllopathic & Osteopathic Physicians

Taxonomy Code207RH0003X

License✔ Licensed in IL · 036-058921

Definition

An internist doctor of osteopathy that specializes in the treatment of the combination of hematology and oncology disorders. A doctor of osteopathy that is board eligible/certified by the American Osteopathic Board of Internal Medicine WAS able to obtain a Certificate of Special Qualifications in the field of Hematology and Oncology. The Certificate is NO longer offered.

1725 W HARRISON ST, Chicago, IL 60612

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Other Identifiers 2

Medicare ID-Type UnspecifiedL68357IL

Medicare UPINC44625IL

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Ambetter Health.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

William T Leslie 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 ID5597703314

PECOS Enrollment IDI20050421001318

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 William Leslie reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Rush University Medical Group

0.2 mi

Internal Medicine

1620 W HARRISON ST
Chicago, IL 60612

Reassigned Medicare billing, Illinois enrollment
2,169 clinicians in this Medicare group

NPI 1093819542 (312) 942-5000

Rush Medical Group

0.2 mi

Internal Medicine

1620 W HARRISON ST
Chicago, IL 60612

Reassigned Medicare billing, Illinois enrollment
548 clinicians in this Medicare group

NPI 1467312850 (312) 942-5000

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 7

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.

Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more 99215

This service involves a follow-up appointment for existing patients, lasting between 40 to 54 minutes. During this time, your healthcare provider will assess your current health status, discuss any changes or concerns, review your treatment plan, and answer any questions you may have.

374 services118 patients

Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more 99215

270 services77 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.

25 services22 patients

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

22 services19 patients

New patient office or other outpatient visit with a high level of medical decision making, if using time, 60 minutes or more 99205

This is a first-time patient visit where a healthcare professional spends 60-74 minutes with you. It involves a comprehensive evaluation, including your medical history and current health condition. They'll also advise on preventive health measures and formulate a treatment plan if needed.

18 services18 patients

New patient office or other outpatient visit with a high level of medical decision making, if using time, 60 minutes or more 99205

16 services16 patients

Hospital Affiliations CMS Care Compare 2

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

Rush Oak Park Hospital

Acute Care Hospitals · Oak Park, IL

4/5 CMS rating

OwnershipVoluntary non-profit - Church

CMS Certification Number140063

Location520 S Maple AveOak Park, IL 60304 · Cook County

Emergency services

Rush University Medical Center

Acute Care Hospitals · Chicago, IL

5/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number140119

Location1653 West Congress ParkwayChicago, IL 60612 · Cook County

Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 60612 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

$183.39 typical visit price

range $60.08 – $183.39

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

Most-billed visit code 99205

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.

Referred Medical Equipment & Supplies CMS DME claims 4

Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.

Ostomy deodorant, with or without lubricant, for use in ostomy pouch, per fluid ounce A4394

DME-Orthotic Devices · category DF010N

4 suppliers12 claims328 services$1.89 avg. paid by Medicare

Adhesive remover, wipes, any type, each A4456

DME-Medical/Surgical Supplies · category DA000N

3 suppliers20 claims920 services$0.21 avg. paid by Medicare

Ostomy pouch, drainable, with extended wear barrier attached, with filter, (1 piece), each A5056

DME-Orthotic Devices · category DF010N

2 suppliers15 claims470 services$4.40 avg. paid by Medicare

Skin barrier, wipes or swabs, each A5120

DME-Orthotic Devices · category DF010N

3 suppliers11 claims295 services$0.15 avg. paid by Medicare

Dollar amounts are the average Medicare paid the supplier per service. They are not the cost to the patient.

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. MARTA BATUS MD

Internal Medicine (Medical Oncology)

1725 W HARRISON ST, SUITE 809
CHICAGO, IL 60612

Cook County (312) 563-2487

KM WILLIAMS MD SC

Clinic/Center (Ophthalmologic Surgery)

1725 W HARRISON ST, STE 910
CHICAGO, IL 60612

Cook County (312) 622-7320

KENNETH M BOYER M.D.

Pediatrics (Pediatric Infectious Diseases)

1725 W HARRISON ST, SUITE 710
CHICAGO, IL 60612

Cook County (312) 942-3034

RUSH UNIVERSITY MEDICAL CENTER

Internal Medicine (Hematology)

1725 W HARRISON ST, SUITE 1010
CHICAGO, IL 60612

Cook County (312) 942-5904

DAVID ANSELL M.D.

Internal Medicine

1725 W HARRISON ST, SUITE 263
CHICAGO, IL 60612

Cook County (312) 942-6700

MIDWEST NEUROPSYCHIATRIC ASSOC LTD

Specialist

1725 W HARRISON ST, SUITE 744
CHICAGO, IL 60612

Cook County (312) 942-0118

JANICE DIESCHBOURG M.D.

Radiology (Diagnostic Radiology)

1725 W HARRISON ST, SUITE 155
CHICAGO, IL 60612

Cook County (312) 563-3269

AFFILIATED UROLOGISTS, LTD

Specialist

1725 W HARRISON ST, SUITE 762
CHICAGO, IL 60612

Cook County (312) 563-3447

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 William Leslie's NPI number?

The NPI number for William Leslie is 1538129275. It was assigned to this individual provider in the NPPES registry on March 25, 2006.

Where is William Leslie located?

William Leslie practices at 1725 W Harrison St Suite 1010, Chicago, IL 60612. The listed phone number is (312) 942-5904.

What is William Leslie's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Hematology & Oncology, with taxonomy code 207RH0003X.

Is William Leslie enrolled in Medicare?

Yes. William Leslie 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 William Leslie's services?

According to the CMS Revalidation Reassignment List (October 2026 release), William Leslie reassigns Medicare benefits to 2 organizations: Rush University Medical Group (Chicago, IL) and Rush Medical Group (Chicago, 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 William Leslie's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does William Leslie accept?

Health plans from Ambetter Health list William Leslie 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 William Leslie affiliated with any hospitals?

According to CMS data, William Leslie is affiliated with Rush Oak Park Hospital and Rush University Medical Center.

When was this NPI record last updated?

The NPPES record for William Leslie was last updated on April 14, 2011. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 15 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.