Dirk Diefendorf, M.D.
NPI 1467559443 · Sports Medicine (Neuromusculoskeletal Medicine) Physician · San Mateo, CA
Enrolled with Medicare as Practitioner - Orthopedic Surgery · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Dirk Diefendorf, M.D. is a Sports Medicine (Neuromusculoskeletal Medicine) Physician provider in San Mateo, CA (NPI 1467559443).
Provider details
- NPI number
- 1467559443
- Entity type
- Individual
- Primary specialty
- Sports Medicine (Neuromusculoskeletal Medicine) PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- G53558 (CA)
Specialties & taxonomies
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
474 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 | 274 | $158 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 89 | $113 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 83 | $206 |
| New Patient Office Or Other Outpatient Visit With Low Level of Medical Decision Making, If Using Time, 30 Minutes Or More99203 | 17 | $139 |
| New Patient Office Or Other Outpatient Visit With a High Level of Medical Decision Making, If Using Time, 60 Minutes Or More99205 | 11 | $269 |
Typical Medicare-allowed amounts for these services range $113–$269 (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 · 5 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Meloxicam | 62 | 31 |
| Cephalexin | 26 | 21 |
| Diclofenac Sodium | 20 | — |
| Tramadol Hcl | 14 | 13 |
| Nabumetone | 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
- 2006-09-20
- Last updated
- 2010-08-30
Frequently asked questions
- What is Dirk Diefendorf's NPI number?
- Dirk Diefendorf's National Provider Identifier (NPI) is 1467559443, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Dirk Diefendorf's specialty?
- Dirk Diefendorf is listed in the NPPES registry with a primary specialty of Sports Medicine (Neuromusculoskeletal Medicine) Physician (Allopathic & Osteopathic Physicians).
- Where is Dirk Diefendorf located?
- Dirk Diefendorf's practice location on file with NPPES is 101 S Ellsworth Ave, San Mateo, CA 94401-3956.
- What is Dirk Diefendorf's phone number?
- The practice phone number listed in the NPPES registry for Dirk Diefendorf is (650) 347-0157.
- Does Dirk Diefendorf accept Medicare?
- Dirk Diefendorf is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Dirk Diefendorf's NPI active?
- Yes — Dirk Diefendorf's NPI (1467559443) is active in the NPPES registry as of the last update on 2010-08-30.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.