Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

William Sanderson Twaddell, MD

Individual provider Anatomic Pathology Physician · NPI 1538296124

William Sanderson Twaddell, MD is a Pathology in Baltimore, Maryland. Graduated from Columbia University College of Physicians and Surgeons in 2004, 22 years ago. Practices with Chester River Hospital Center, a 30-clinician group and accepts Medicare assignment. Licensed in Maryland and New York.

Years since qualifying
22
Trained at
Columbia University College of Physicians and Surgeons
Licensed in
MD, NY
In the registry since
2007
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

See every abbreviation used in this directory →

Practice location Address checks out

22 S Greene St NBW73
Baltimore, MD 21201-1544
Phone: (410) 328-5555
Fax: (410) 328-0929
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Anatomic Pathology & Clinical Pathology Physician (primary) Taxonomy 207ZP0102X · Licence D68076 (MD)
Anatomic Pathology Physician Taxonomy 207ZP0101X · Licence 242497-1 (NY)

Record details

NPI number1538296124
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedFebruary 28, 2007
Last updated in NPPESMay 7, 2026
Certification dateMay 7, 2026

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyPATHOLOGY
Medical schoolCOLUMBIA UNIVERSITY COLLEGE OF PHYSICIANS AND SURGEONS
Graduated 2004 (22 years in practice)
Group practice Chester River Hospital Center — 30 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations3 on file with Medicare

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