Mark Williams, MD, PHD
NPI 1417986001 · Surgery Physician · Muscatine, IA
Enrolled with Medicare as Practitioner - General Surgery · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Williams, MD, PHD is a Surgery Physician provider in Muscatine, IA (NPI 1417986001).
Provider details
- NPI number
- 1417986001
- Entity type
- Individual
- Primary specialty
- Surgery PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD, PHD
- Sex
- Male
- Sole proprietor
- Yes
- License
- 49587 (IA)
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
80 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) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 23 | $73 |
| Initial Hospital Care With Straightforward Or Low-Level Medical Decision Making, If Using Time, at Least 55 Minutes99222 | 15 | $120 |
| Colorectal Cancer Screening; Colonoscopy on Individual Not Meeting Criteria for High RiskG0121 | 15 | $165 |
| Removal of Polyps Or Growths of Large Bowel Using an Endoscope With Mechanical Snare45385 | 14 | $228 |
| Biopsy of Large Bowel Using a Flexible Endoscope45380 | 13 | $129 |
Typical Medicare-allowed amounts for these services range $73–$228 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 2 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 33 | 33 |
| Tramadol Hcl | 12 | 11 |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-07-03
- Last updated
- 2025-11-14
- Certified
- 2025-11-14
Frequently asked questions
- What is Mark Williams's NPI number?
- Mark Williams's National Provider Identifier (NPI) is 1417986001, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Williams's specialty?
- Mark Williams is listed in the NPPES registry with a primary specialty of Surgery Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Williams located?
- Mark Williams's practice location on file with NPPES is 1518 Mulberry Ave Ste 102, Muscatine, IA 52761-3433.
- What is Mark Williams's phone number?
- The practice phone number listed in the NPPES registry for Mark Williams is (563) 264-4112.
- Does Mark Williams accept Medicare?
- Mark Williams is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Williams's NPI active?
- Yes — Mark Williams's NPI (1417986001) is active in the NPPES registry as of the last update on 2025-11-14.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.