William Johnston, M.D.
Emergency Medicine Physician · Palo Alto, CA
William Johnston, M.D. is an emergency medicine physician with a practice address in Palo Alto, California, and NPI 1417366584, issued on Aug 3, 2014. Check the license (California A138944, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- William Johnston
- Credential
- M.D.
- Primary taxonomy
- Emergency Medicine Physician 207P00000X
- License number
- A138944 CA
Self-reported in NPPES; status is on the state search - Practice location
- 3801 Miranda Ave, Palo Alto, CA 94304
- Phone
- (650) 493-5000
- Enumerated
- Aug 3, 2014
- Record last updated
- Aug 12, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20161010000813); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest emergency medicine physician records → All 7,751 in California → Look up another NPI →
Also registered at 3801 Miranda Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Steven Abadi, DPMFoot & Ankle Surgery Podiatrist1922729383
- Nidhu Abraham, PHARM.D., BCPSPharmacotherapy Pharmacist1023543717
- Simon Abramson, MDDiagnostic Radiology Physician1609106137
- Christelle Jade AbrenicaInfusion Therapy Registered Nurse1770470411
- Laurie Ackerman, LCSWClinical Social Worker1699797001
- Russell Acob, RNRegistered Nurse1235757154
Verify William Johnston in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A138944Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
84% fewer Medicare Part D claims than the average emergency medicine physician in 2024
37 Medicare Part D claims for 23 beneficiaries, against an average of 226 among the 54,106 providers of this specialty who prescribed in Part D.
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): 94.6 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.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Bills Medicare through one group practice
- Cep America - CaliforniaSan Mateo, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
William Johnston among 7,751 emergency medicine physician records in California
William Johnston, M.D. is one of 7,751 emergency medicine physician records with a practice address in California. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2014, is newer than 69% of them.
- NPI issued2014 · 69% of these records are older, 28% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 59% of these records are
- Graduated2013 · median 2011 among the 4,560 with a school on file
- Record last updated2021 · 59% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207P00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Emergency Medicine Physician providers in California
There are 7,751 emergency medicine physician records in California.
All 7,751 in California → Every provider in Palo Alto → Emergency Medicine Physician nationwide →
The 8 emergency medicine physician records with the nearest ZIP codes
- Terence Ahern, MDPalo Alto, CA 943041104195916
- Christopher Evans, D.O.Palo Alto, CA 943041902227788
- Tonia Fox, MDPalo Alto, CA 943041023050242
- Derrick Lung, MDPalo Alto, CA 943041821259342
- Anne Merritt, M.D.Palo Alto, CA 943041730322967
- Robert Norris, M.D.Palo Alto, CA 943041124177928
- Sabrina Pak, MDPalo Alto, CA 943041548332018
- Zina Semenovskaya, MDPalo Alto, CA 943041255560181
Common questions
What is William Johnston, M.D.'s NPI number?
William Johnston, M.D.'s National Provider Identifier (NPI) is 1417366584, issued on Aug 3, 2014. An NPI identifies a provider in billing; it is not a license.
Where is William Johnston, M.D. located?
The NPPES record lists a practice address at 3801 Miranda Ave, Palo Alto, CA, 94304. Phone: (650) 493-5000. Providers update this record themselves, so call before visiting.
How can I verify William Johnston, M.D.'s license?
NPPES lists California license number A138944, 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 William Johnston, M.D. prescribe under Medicare Part D?
In 2024, William Johnston, M.D. had 37 Medicare Part D claims for 23 beneficiaries; the average among emergency medicine physician prescribers was 226. Part D covers Medicare prescriptions only.
What is William Johnston, M.D.'s MIPS final score?
The 2023 MIPS final score is 94.6 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.