NPPES file of Aug 9, 2026

Ken Zafren, MD

Emergency Medicine Physician · Stanford, CA

Ken Zafren, MD is an emergency medicine physician with a practice address in Stanford, California, and NPI 1366466120, issued on Jul 26, 2006. Check the license (California G70948, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2023 and 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1366466120
Name
Ken Zafren
Credential
MD
Primary taxonomy
Emergency Medicine Physician 207P00000X
License numbers
G70948 CA
2181 AK
Self-reported in NPPES; status is on the state search
Practice location
300 Pasteur Dr, Stanford, CA 94305
Phone
(650) 723-0000
Enumerated
Jul 26, 2006
Record last updated
Mar 21, 2024
Medicaid ID
MD21813 AK
Medicare enrollment
Enrolled (PECOS I20090513000509); accepts Medicare assignment
Medical or professional school
University Of Washington School Of Medicine, 1984
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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Also registered at 300 Pasteur Dr

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Cooper Aakhus, MDEmergency Medicine Physician1194351007
  2. Oliver Aalami, M.D.Vascular Surgery Physician1225229024
  3. Alistair Aaronson, MDInternal Medicine Physician1457628760
  4. Sumaira Aasi, MDMOHS-Micrographic Surgery Physician1780675181
  5. Fahim Abbasi, M.D.Internal Medicine Physician1841484037
  6. Mohamad Abbass, MDNeurological Surgery Physician1679492151

Verify Ken Zafren in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of California
    Search for license G70948
    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the California license search

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78% fewer Medicare Part D claims than the average emergency medicine physician in 2024

50 Medicare Part D claims, against an average of 226 among the 54,106 providers of this specialty who prescribed in Part D. Brand-name drugs were 0% of claims.

  1. Ken Zafren50
  2. Specialty average226

Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.

The practice group's MIPS final score for 2023 (Medicare payment program): 76.5 of 100

The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.

  1. Qualityout of 100 · 30% of the final score74.3
  2. Costout of 100 · 30%44.0
  3. Promoting interoperabilityout of 100 · 25%100.0
  4. Improvement activities40 of 40 points · 15%100.0

Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).

One hospital affiliation

  1. Stanford Health CareStanford, CA · Acute Care Hospitals5 of 5 stars

Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through); hospitals matched to CMS Hospital General Information (Care Compare) (data.cms.gov). Star ratings are CMS hospital ratings, not ratings of this provider.

163 emergency medicine physician records list a practice address in Stanford

They are 163 of the 5,606 NPPES records with a practice address in Stanford, and 7,751 emergency medicine physician records in California.

Other emergency medicine physician records in California

  1. Cooper Aakhus, MDStanford, CA1194351007
  2. Pyra Aarden, MDMartinez, CA1417058199
  3. Neal Aaron, D.O.Encinitas, CA1114283520
  4. Eric AaserudeWalnut Creek, CA1811491194
  5. Nader Abas, MDBarstow, CA1346288305
  6. Michael Abbo, MDNovato, CA1205819042
  7. Daniel Abbott, MDFullerton, CA1518907864
  8. Paul-Andre Abboud, M.D.Oakland, CA1710065503
  9. Mostafa Abdel-Hamid, MDStanford, CA1457918740
  10. Ashraf Abdel-KerimChino, CA1396961538

Common questions

What is Ken Zafren, MD's NPI number?

Ken Zafren, MD's National Provider Identifier (NPI) is 1366466120, issued on Jul 26, 2006. An NPI identifies a provider in billing; it is not a license.

Where is Ken Zafren, MD located?

The NPPES record lists a practice address at 300 Pasteur Dr, Stanford, CA, 94305. Phone: (650) 723-0000. Providers update this record themselves, so call before visiting.

How can I verify Ken Zafren, MD's license?

NPPES lists California license number G70948, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does Ken Zafren, MD prescribe under Medicare Part D?

In 2024, Ken Zafren, MD had 50 Medicare Part D claims; the average among emergency medicine physician prescribers was 226. Part D covers Medicare prescriptions only.

What is Ken Zafren, MD's MIPS final score?

The 2023 MIPS final score is 76.5 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.

Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.