NPI registry status
Active
2026 NPPES data Critical Care Medicine (Anesthesiology) Physician NPI 1356309140 MD
Verify on CMS → C. Spencer Yost, MD
Critical Care Medicine (Anesthesiology) Physician in San Francisco, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 1,397 in Critical Care Medicine (Anesthesiology) Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
What the federal data shows
C. Spencer Yost, MD is a Critical Care Medicine (Anesthesiology) Physician in San Francisco, California, listed in the federal CMS National Provider Identifier registry.
- #217
- Critical Care Medicine (Anesthesiology) Physician rank among California specialties
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Federal trust snapshot
What official records show about C. Spencer Yost, MD
Bare NPI registry listing — limited federal enrichment beyond basic enumeration. Verify all credentials with official sources.
- Verified
NPI registry status
Active listing in the CMS National Provider Identifier Registry (NPI 1356309140), first enumerated 05/02/2006.
Source: CMS NPPES
- Not in federal data
Medicare Part D participation
No 2023 Medicare Part D prescribing volume appears in the CMS public file for this NPI (may reflect specialty, new enrollment, or non-prescribing role).
Source: CMS Part D Prescriber PUF
- Reported
Board certification signal
Practices in an ABMS-board-eligible specialty; board certification not confirmed in federal records.
- State context
State board disciplinary context
California statewide board action statistics are published annually — these figures describe aggregate state activity, not C. Spencer Yost, MD's individual license status. Verify directly with the state medical board.
Source: MBC annual report 2023
- Not in federal data
Individual sanction lookup
PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.
Source: State medical board / FSMB
This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.
CMS NPPES provider registry desk
NPI 1356309140 · Critical Care Medicine (Anesthesiology) Physician
NPI-10 · ENUM-LEGACY · TAX-NARROW · RX-NONE · BOOK-THIN · PHOTO-ENUM
- NPI-10 1356309140
- ENUM-LEGACY 2006
- TAX-NARROW 1,397
- RX-NONE No Part D
- BOOK-THIN 159 in California
- PHOTO-ENUM George Tseng · 2006
◑
Board-eligible specialty (heuristic, not verified)
C. Spencer Yost, MD practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about C. Spencer Yost, MD?
Quality data not reportedPrimary specialty
Critical Care Medicine (Anesthesiology) Physician
Specialty distribution in California
How Critical Care Medicine (Anesthesiology) Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Critical Care Medicine (Anesthesiology) Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Practice Address
Provider Details
| NPI | 1356309140 |
|---|---|
| Specialty | Critical Care Medicine (Anesthesiology) Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 05/02/2006 |
License & disciplinary context - California MBC 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 - they are NOT specific to C. Spencer Yost, MD. To verify C. Spencer Yost, MD's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases
MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
More Critical Care Medicine (Anesthesiology) Physician in CA →
All providers in California →
Compare specialties →
Critical Care Medicine (Anesthesiology) Physician Overview
How C. Spencer Yost, MD fits within the Critical Care Medicine (Anesthesiology) Physician landscape nationally.
1,397
Critical Care Medicine (Anesthesiology) Physician Providers in US
46
States with Critical Care Medicine (Anesthesiology) Physician
409
Avg Claims per Provider
Nationwide Critical Care Medicine (Anesthesiology) Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for Yost, both outside California so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2006)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Critical Care Medicine (Anesthesiology) Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Yost.
One of 159 Critical Care Medicine (Anesthesiology) Physician providers enrolled in California, 5 are shown here.
Frequently Asked Questions
What is C. Spencer Yost, MD's specialty? ▼
C. Spencer Yost, MD specializes in Critical Care Medicine (Anesthesiology) Physician and practices in San Francisco, California. Credentials: MD.
Where is C. Spencer Yost, MD located? ▼
C. Spencer Yost, MD is located at 513 PARNASSUS AVE, San Francisco, CA, 94143. Phone: (415) 476-9035.
What is C. Spencer Yost, MD's NPI number? ▼
C. Spencer Yost, MD's National Provider Identifier (NPI) is 1356309140, issued on 05/02/2006.
How many Critical Care Medicine (Anesthesiology) Physician providers are there in the US? ▼
There are 1,397 Critical Care Medicine (Anesthesiology) Physician providers across 46 states in the US. The average Critical Care Medicine (Anesthesiology) Physician provider writes 409 Medicare Part D claims per year.
Does C. Spencer Yost, MD accept Medicare? ▼
C. Spencer Yost, MD appears in CMS Medicare data. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify C. Spencer Yost, MD's credentials? ▼
C. Spencer Yost, MD's NPI is 1356309140 with credentials MD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.