L Warren, MD
NPI 1558341933 · Family Medicine Physician · Belvidere, IL
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
L Warren, MD is a Family Medicine Physician provider in Belvidere, IL (NPI 1558341933).
Provider details
- NPI number
- 1558341933
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 036061249 (IL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
20 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
262 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
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 .
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 Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 156 | $123 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 47 | $87 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 45 | $124 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 14 | $173 |
Typical Medicare-allowed amounts for these services range $87–$173 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote 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 · 35 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 138 | 40 |
| Metoprolol Succinate | 82 | 22 |
| Amlodipine Besylate | 74 | 22 |
| Levothyroxine Sodium | 73 | 22 |
| Losartan Potassium | 64 | 20 |
| Lisinopril | 51 | 17 |
| Amlodipine Besylate/Benazepril |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$1,301 across 35 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-01-20
- Last updated
- 2007-07-18
Frequently asked questions
- What is L Warren's NPI number?
- L Warren's National Provider Identifier (NPI) is 1558341933, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is L Warren's specialty?
- L Warren is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is L Warren located?
- L Warren's practice location on file with NPPES is 205 Cadillac Ct, Belvidere, IL 61008-1733.
- What is L Warren's phone number?
- The practice phone number listed in the NPPES registry for L Warren is (815) 544-0444.
- Does L Warren accept Medicare?
- L Warren is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is L Warren's NPI active?
- Yes — L Warren's NPI (1558341933) is active in the NPPES registry as of the last update on 2007-07-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.