William Twaddell, M.D.
NPI 1538296124 · Anatomic Pathology & Clinical Pathology Physician · Baltimore, MD
Enrolled with Medicare as Practitioner - Pathology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Twaddell, M.D. is a Anatomic Pathology & Clinical Pathology Physician provider in Baltimore, MD (NPI 1538296124).
Provider details
- NPI number
- 1538296124
- Entity type
- Individual
- Primary specialty
- Anatomic Pathology & Clinical Pathology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 242497-1 (NY)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
2,749 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Pathology Examination of Tissue Using a Microscope, Intermediate Complexity88305 | 1,073 | $37 |
| Special Stained Specimen Slides to Examine Tissue, Each Additional Procedure88341 | 310 | $28 |
| Pathology Examination of Tissue Using a Microscope, Moderately High Complexity88307 | 230 | $80 |
| Special Stained Specimen Slides to Examine Tissue, Initial Procedure88342 | 206 | $34 |
| Special Stained Specimen Slides to Examine Tissue Including Interpretation and Report88313 | 191 | $12 |
| Pathology Examination of Specimen During Surgery, First Tissue Block88331 | 152 | $60 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2007-02-28
- Last updated
- 2026-05-07
- Certified
- 2026-05-07
Frequently asked questions
- What is William Twaddell's NPI number?
- William Twaddell's National Provider Identifier (NPI) is 1538296124, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Twaddell's specialty?
- William Twaddell is listed in the NPPES registry with a primary specialty of Anatomic Pathology & Clinical Pathology Physician (Allopathic & Osteopathic Physicians).
- Where is William Twaddell located?
- William Twaddell's practice location on file with NPPES is 22 S Greene St, Baltimore, MD 21201-1544.
- What is William Twaddell's phone number?
- The practice phone number listed in the NPPES registry for William Twaddell is (410) 328-5555.
- Does William Twaddell accept Medicare?
- William Twaddell is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Twaddell's NPI active?
- Yes — William Twaddell's NPI (1538296124) is active in the NPPES registry as of the last update on 2026-05-07.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.