William Seiden, MD
NPI 1407915978 · Internal Medicine Physician · Lake Forest, IL
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Seiden, MD is a Internal Medicine Physician provider in Lake Forest, IL (NPI 1407915978).
Provider details
- NPI number
- 1407915978
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 036086127 (IL)
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
1,601 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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 291 | $191 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 278 | $135 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 228 | $138 |
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 220 | $17 |
| Insertion of Needle Into Vein for Collection of Blood Sample36415 | 199 | $9 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 51 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 554 | 170 |
| Amlodipine Besylate | 199 | 58 |
| Losartan Potassium | 184 | 50 |
| Levothyroxine Sodium | 147 | 41 |
| Lisinopril | 142 | 41 |
| Omeprazole | 128 | 45 |
| Pantoprazole Sodium |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-12-08
- Last updated
- 2022-07-21
Frequently asked questions
- What is William Seiden's NPI number?
- William Seiden's National Provider Identifier (NPI) is 1407915978, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Seiden's specialty?
- William Seiden is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is William Seiden located?
- William Seiden's practice location on file with NPPES is 800 N Westmoreland Rd Ste 201, Lake Forest, IL 60045-1687.
- What is William Seiden's phone number?
- The practice phone number listed in the NPPES registry for William Seiden is (608) 242-6850.
- Does William Seiden accept Medicare?
- William Seiden is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Seiden's NPI active?
- Yes — William Seiden's NPI (1407915978) is active in the NPPES registry as of the last update on 2022-07-21.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.