Quick answers
- Does Nicholas F. Callahan accept Medicare assignment?
- Yes. Medicare's clinician data says Nicholas F. Callahan accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does Nicholas F. Callahan see?
- In 2024, CMS data shows 79 Original Medicare patients and 168 services for Nicholas F. Callahan. This counts Original Medicare only and measures volume, not quality.
- What is Nicholas F. Callahan's NPI number?
- 1083920227. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for Nicholas F. Callahan, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 79 |
|---|---|
| Services billed to Medicare | 168 |
| Different services or procedures | 44 |
| Participating Medicare provider | Yes |
| Average age of these patients | 70 |
Most frequent services
- Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more (99212)36 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)17 services
- Ct scan of face without contrast (70486)16 services
- New patient office or other outpatient visit with low level of medical decision making, if using time, 30 minutes or more (99203)11 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- High blood pressure70%
- High cholesterol70%
- Arthritis42%
- Diabetes30%
- Depression30%
- Anxiety29%
Hospitals where Nicholas F. Callahan works
Medicare's Facility Affiliation Data lists Nicholas F. Callahan at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- University of Illinois Hospital and ClinicsChicago, IL · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 140150
Practice locations
Addresses where Nicholas F. Callahan is enrolled with Medicare (CMS data updated October 2, 2026).
- 1740 W Taylor StChicago, IL 60612
- 1855 W Taylor StChicago, IL 60612 (312) 996‑6590
- 1855 W Taylor St, Mc648Chicago, IL 60612 (312) 996‑6590
- 801 S Paulina StChicago, IL 60612 (312) 996‑7532
- 801 S Paulina St, Mc 621 Rm 42Chicago, IL 60612 (312) 996‑6519
Group practices
Medicare enrollment lists Nicholas F. Callahan as a member of this group (CMS data updated October 2, 2026).
- The Board of Trustees of the University of Illinois1,150 clinicians in the group
Specialties
- Maxillofacial Surgeryprimary
Other maxillofacial surgeons in Chicago
Clinicians with the same Medicare primary specialty in Chicago, IL — not a recommendation.
Other clinicians in The Board of Trustees of the University of Illinois
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | State University Of New York Downstate Medical Center |
| Graduation year | 2013 (13 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1083920227 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians