Doctor profile · Federal record

Dr. William Twaddell, M.D.

Anatomic Pathology & Clinical Pathology Physician (CMS: Pathology) · Anatomic Pathology Physician · Baltimore, MD

  • NPI 1538296124
  • Accepts Medicare
  • 22 yrs in practice
  • Licensed in 2 states
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
22 S Greene St, Nbw73
Baltimore, MD 212011544
(410) 328-5555
fax (410) 328-0929

Credentials & registration

NPPES · NUCC
NPI registered
February 2007 — 19 yrs on file
Profile last updated
January 25, 2011
Year of graduation
2004 — 22 yrs since
Specialty taxonomy
207ZP0102X — NUCC code
State licenses (2)
Maryland #D68076 · New York #242497-1

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1538296124. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
1,733
Distinct HCPCS
10
Medicare allowed
$79,242
HCPCS Description Services Patients Avg allowed
88305 Pathology examination of tissue using a microscope, intermediate complexity 781 381 $38
88307 Pathology examination of tissue using a microscope, moderately high complexity 189 151 $85
88331 Pathology examination of specimen during surgery, first tissue block 164 62 $64
88313 Special stained specimen slides to examine tissue including interpretation and report 112 37 $12
88342 Special stained specimen slides to examine tissue, initial procedure 106 81 $35
88341 Special stained specimen slides to examine tissue, each additional procedure 91 36 $29
88304 Pathology examination of tissue using a microscope, moderately low complexity 90 78 $12
88309 Pathology examination of tissue using a microscope, high complexity 86 80 $149
88311 Preparation of tissue for examination by removing any calcium present 68 63 $13
88300 Pathology examination of tissue using a microscope, limited examination 28 27 $5

In context: peer comparison

Among 49 peers in Baltimore Anatomic Pathology & Clinical Pathology Physician, average services per provider: 135. This provider delivers 13× the peer median.

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. William Twaddell's medical specialty?
Dr. William Twaddell practices Anatomic Pathology & Clinical Pathology Physician in Baltimore, MD.
Where does Dr. William Twaddell practice?
Dr. William Twaddell practices at 22 S Greene St, Baltimore, MD 212011544. Office phone: 4103285555.
What is Dr. William Twaddell's NPI?
Dr. William Twaddell's National Provider Identifier (NPI) is 1538296124, issued by NPPES.
Does Dr. William Twaddell accept Medicare assignment?
Yes. Dr. William Twaddell accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. William Twaddell commonly perform?
Top Medicare-reported procedures in 2023: Pathology examination of tissue using a microscope, intermediate complexity (HCPCS 88305); Pathology examination of tissue using a microscope, moderately high complexity (HCPCS 88307); Pathology examination of specimen during surgery, first tissue block (HCPCS 88331). Source: CMS Medicare Physician & Other Practitioners file.