William Larsen, FNP
NPI 1124409099 · Family Nurse Practitioner · Ithaca, NY
Enrolled with Medicare as Practitioner - Nurse Practitioner · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Larsen, FNP is a Family Nurse Practitioner provider in Ithaca, NY (NPI 1124409099).
Provider details
- NPI number
- 1124409099
- Entity type
- Individual
- Primary specialty
- Family Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- FNP
- Sex
- Male
- Sole proprietor
- Yes
- License
- 339752 (NY)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
11 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)28% of score
743 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 Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 306 | $103 |
| Hemoglobin A1c Level83036 | 258 | $9 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 93 | $73 |
| Continuous Monitoring of Blood Sugar Level in Tissue Fluid Using Sensor Under Skin With Interpretation and Report95251 | 86 | $27 |
Typical Medicare-allowed amounts for these services range $9–$103 (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 · 52 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Semaglutidebrand: Ozempic | 285 | 50 |
| Levothyroxine Sodium | 240 | 54 |
| Metformin Hcl | 178 | 51 |
| Empagliflozinbrand: Jardiance | 169 | 46 |
| Dulaglutidebrand: Trulicity | 150 | 30 |
| Insulin Glargine,hum.rec.anlogbrand: Lantus Solostar | 129 | 46 |
Practice location
Mailing address
Additional practice locations (1)
- 404 N Cayuga StIthaca, NY 14850-4219Phone: (607) 277-0969Fax: (607) 277-3242
Registry dates
- Enumerated
- 2015-06-16
- Last updated
- 2022-08-23
- Certified
- 2022-08-23
Frequently asked questions
- What is William Larsen's NPI number?
- William Larsen's National Provider Identifier (NPI) is 1124409099, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Larsen's specialty?
- William Larsen is listed in the NPPES registry with a primary specialty of Family Nurse Practitioner (Physician Assistants & Advanced Practice Nursing Providers).
- Where is William Larsen located?
- William Larsen's practice location on file with NPPES is 905 Hanshaw Rd, Ithaca, NY 14850-1549.
- What is William Larsen's phone number?
- The practice phone number listed in the NPPES registry for William Larsen is (607) 339-0670.
- Does William Larsen accept Medicare?
- William Larsen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Larsen's NPI active?
- Yes — William Larsen's NPI (1124409099) is active in the NPPES registry as of the last update on 2022-08-23.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.