Diane Ashley Mar, MD
Rheumatology Physician · Stanford, CA
Diane Ashley Mar, MD is a rheumatology physician with a practice address in Stanford, California, and NPI 1356704795, issued on Apr 2, 2016. Check the license (California A161922, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Diane Ashley Mar
- Credential
- MD
- Primary taxonomy
- Rheumatology Physician 207RR0500X
- License number
- A161922 CA
Self-reported in NPPES; status is on the state search - Practice location
- 300 Pasteur Dr, Stanford, CA 94305
- Phone
- (650) 723-4000
- Enumerated
- Apr 2, 2016
- Record last updated
- Apr 15, 2024
- Medicare enrollment
- Enrolled (PECOS I20210611002075); accepts Medicare assignment
- Medical or professional school
- University Of Nevada School Of Medicine, 2016
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest rheumatology physician records → All 926 in California → Look up another NPI →
Also registered at 300 Pasteur Dr
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Verify Diane Ashley Mar in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A161922Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
86% fewer Medicare Part D claims than the average rheumatology physician in 2024
278 Medicare Part D claims for 43 beneficiaries, against an average of 1,978 among the 6,301 providers of this specialty who prescribed in Part D. Brand-name drugs were 22% of claims. 12 claims were for opioids.
Most prescribed
- Prednisone41 claims
- Hydroxychloroquine Sulfate33 claims
- Allopurinol29 claims
- Actemra Actpen16 claims
- Leflunomide13 claims
- Methotrexate13 claims
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.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Bills Medicare through one group practice
- County OF Santa ClaraSan Jose, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Diane Ashley Mar among 926 rheumatology physician records in California
Diane Ashley Mar, MD is one of 926 rheumatology 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 2016, is newer than 85% of them.
- NPI issued2016 · 85% of these records are older, 12% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 69% of these records are
- Graduated2016 · median 2003 among the 641 with a school on file
- Record last updated2024 · 62% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RR0500X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Rheumatology Physician providers in California
There are 926 rheumatology physician records in California.
All 926 in California → Every provider in Stanford → Rheumatology Physician nationwide →
The 8 rheumatology physician records with the nearest ZIP codes
- Matthew Baker, MDStanford, CA 943051518252204
- Yashaar Chaichian, MDStanford, CA 943051174788103
- Mark Genovese, M.D.Stanford, CA 943051487711875
- Jorg Goronzy, M.D.Stanford, CA 943051720097124
- Jison Hong, MDStanford, CA 943051740441823
- Tamiko Katsumoto, M.D.Stanford, CA 943051952571317
- Victoria Kelly, M.D.Stanford, CA 943051366622193
- Janice Lin, M.D.Stanford, CA 943051427217223
Common questions
What is Diane Ashley Mar, MD's NPI number?
Diane Ashley Mar, MD's National Provider Identifier (NPI) is 1356704795, issued on Apr 2, 2016. An NPI identifies a provider in billing; it is not a license.
Where is Diane Ashley Mar, MD located?
The NPPES record lists a practice address at 300 Pasteur Dr, Stanford, CA, 94305. Phone: (650) 723-4000. Providers update this record themselves, so call before visiting.
How can I verify Diane Ashley Mar, MD's license?
NPPES lists California license number A161922, 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 Diane Ashley Mar, MD prescribe under Medicare Part D?
In 2024, Diane Ashley Mar, MD had 278 Medicare Part D claims for 43 beneficiaries; the average among rheumatology physician prescribers was 1,978. Part D covers Medicare prescriptions only.
What is Diane Ashley Mar, 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.