Michael Duffin, M.D.
NPI 1578587309 · Rheumatology Physician · Torrance, CA
Enrolled with Medicare as Practitioner - Rheumatology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Michael Duffin, M.D. is a Rheumatology Physician provider in Torrance, CA (NPI 1578587309).
Provider details
- NPI number
- 1578587309
- Entity type
- Individual
- Primary specialty
- Rheumatology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- G063443 (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
841 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 Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 332 | $64 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 210 | $94 |
| Established Patient Office Or Other Outpatient Visit With Straightforward Medical Decision Making, If Using Time, 10 Minutes Or More99212 | 151 | $34 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 45 | $130 |
| New Patient Office Or Other Outpatient Visit With Low Level of Medical Decision Making, If Using Time, 30 Minutes Or More99203 | 31 | $80 |
| Aspiration And/Or Injection of Fluid From Large Joint |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 47 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 622 | 69 |
| Prednisone | 479 | 131 |
| Methotrexate Sodiumbrand: Methotrexate | 457 | 117 |
| Tramadol Hcl | 317 | 57 |
| Hydroxychloroquine Sulfate | 297 | 82 |
| Leflunomide | 240 | 63 |
| Gabapentin |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-07-26
- Last updated
- 2012-11-05
Frequently asked questions
- What is Michael Duffin's NPI number?
- Michael Duffin's National Provider Identifier (NPI) is 1578587309, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Michael Duffin's specialty?
- Michael Duffin is listed in the NPPES registry with a primary specialty of Rheumatology Physician (Allopathic & Osteopathic Physicians).
- Where is Michael Duffin located?
- Michael Duffin's practice location on file with NPPES is 3565 Del Amo Blvd, Torrance, CA 90503-1637.
- What is Michael Duffin's phone number?
- The practice phone number listed in the NPPES registry for Michael Duffin is (310) 214-0811.
- Does Michael Duffin accept Medicare?
- Michael Duffin is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Michael Duffin's NPI active?
- Yes — Michael Duffin's NPI (1578587309) is active in the NPPES registry as of the last update on 2012-11-05.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.