Quick answers
- Which hospitals does William S. Twaddell work at?
- Medicare's official clinician data lists William S. Twaddell at 5 hospitals: Johns Hopkins Howard County Medical Center, University of Maryland Medical Center, University of MD Charles Regional Medical Center, University of MD Medical Center Midtown Campus and University of MD Shore Medical Center at Easton. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does William S. Twaddell see patients?
- Medicare's clinician data lists 3 practice locations, including Chestertown, MD, Baltimore, MD and Frederick, MD. Call before your visit to confirm the address.
- What is William S. Twaddell's specialty?
- Medicare lists Pathology as the primary specialty.
- Does William S. Twaddell accept Medicare assignment?
- Yes. Medicare's clinician data says William S. Twaddell accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for William S. Twaddell?
- (410) 778-3300, as listed in official Medicare / NPI Registry data.
- What is William S. Twaddell's NPI number?
- 1538296124. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where William S. Twaddell works
Medicare's Facility Affiliation Data lists William S. Twaddell at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Johns Hopkins Howard County Medical CenterColumbia, MD · Acute Care Hospital · CCN 210048
- University of Maryland Medical CenterBaltimore, MD · Acute Care Hospital · CCN 210002
- University of MD Charles Regional Medical CenterLa Plata, MD · Acute Care Hospital · CCN 210035
- University of MD Medical Center Midtown CampusBaltimore, MD · Acute Care Hospital · CCN 210038
- University of MD Shore Medical Center at EastonEaston, MD · Acute Care Hospital · CCN 210037
Practice locations
Addresses where William S. Twaddell is enrolled with Medicare (CMS data updated 2026-10-02).
- 100 Brown StChestertown, MD 21620 (410) 778‑3300
- 22 S Green StBaltimore, MD 21201 (410) 328‑5555
- 804 Toll House AveFrederick, MD 21701 (301) 695‑7000
Group practices
Medicare enrollment lists William S. Twaddell as a member of these groups (CMS data updated 2026-10-02).
- Chester River Hospital Center28 clinicians in the group
- Univ of MD Pathology Associates P A24 clinicians in the group
- Digestive Disease Solutions LLC3 clinicians in the group
Specialties
- Pathologyprimary
Other pathologists in Chestertown
Clinicians with the same Medicare primary specialty in Chestertown, MD — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Columbia University College Of Physicians And Surgeons |
| Graduation year | 2004 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1538296124 |
| 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 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- 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