Michael Chaffin, N.P.
NPI 1558640235 · Nurse Practitioner · Mountain View, CA
Enrolled with Medicare as Practitioner - Nurse Practitioner · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Michael Chaffin, N.P. is a Nurse Practitioner provider in Mountain View, CA (NPI 1558640235).
Provider details
- NPI number
- 1558640235
- Entity type
- Individual
- Primary specialty
- Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- N.P.
- Sex
- Male
- Sole proprietor
- No
- License
- 20962 (CA)
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 tenure25% of score
14 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)25% of score
189 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) |
|---|---|---|
| Anticoagulant Management of Patient Taking Warfarin93793 | 189 | $12 |
Typical Medicare-allowed amounts for these services range $12–$12 (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 · 3 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Warfarin Sodium | 47 | 33 |
| Enoxaparin Sodium | 26 | 20 |
| Clopidogrel Bisulfatebrand: Clopidogrel | 13 | — |
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.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$36 across 1 record (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
Additional practice locations (1)
- 2540 East StConcord, CA 94520-1906Phone: (925) 682-8200
Registry dates
- Enumerated
- 2011-08-11
- Last updated
- 2024-04-03
- Certified
- 2024-04-03
Frequently asked questions
- What is Michael Chaffin's NPI number?
- Michael Chaffin's National Provider Identifier (NPI) is 1558640235, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Michael Chaffin's specialty?
- Michael Chaffin is listed in the NPPES registry with a primary specialty of Nurse Practitioner (Physician Assistants & Advanced Practice Nursing Providers).
- Where is Michael Chaffin located?
- Michael Chaffin's practice location on file with NPPES is 701 E El Camino Real, Mountain View, CA 94040-2833.
- What is Michael Chaffin's phone number?
- The practice phone number listed in the NPPES registry for Michael Chaffin is (650) 934-7150.
- Does Michael Chaffin accept Medicare?
- Michael Chaffin is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Michael Chaffin's NPI active?
- Yes — Michael Chaffin's NPI (1558640235) is active in the NPPES registry as of the last update on 2024-04-03.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.