Nancy Elizabeth Mason, MD
Obstetrics & Gynecology Physician · Palo Alto, CA
Nancy Elizabeth Mason, MD is an obstetrics & gynecology physician with a practice address in Palo Alto, California, and NPI 1649312067, issued on Feb 13, 2007. Check the license (California G38836, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Nancy Elizabeth Mason
- Credential
- MD
- Primary taxonomy
- Obstetrics & Gynecology Physician 207V00000X
- License number
- G38836 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1101 Welch RD, Palo Alto, CA 94304
- Phone
- (650) 329-1293
- Enumerated
- Feb 13, 2007
- Record last updated
- Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
- Fax
- (650) 329-1317
- Medicare enrollment
- Enrolled (PECOS I20050805000569); accepts Medicare assignment
- Medical or professional school
- Stanford University School Of Medicine, 1977
- Entity
- Type 1 · individual
8 nearest obstetrics & gynecology physician records → All 5,088 in California → Look up another NPI →
Also registered at 1101 Welch RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Nancy Elizabeth Mason in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G38836Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
71% fewer Medicare Part D claims than the average obstetrics & gynecology physician in 2024
48 Medicare Part D claims for 14 beneficiaries, against an average of 165 among the 28,733 providers of this specialty who prescribed in Part D. Brand-name drugs were 23% of claims.
Most prescribed
- Estradiol (Once Weekly)18 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.
Industry payments in 2024: $124.83
1 payment: food and beverage; the largest payer was Mayne Pharma Commercial LLC. The 21,429 providers of this specialty with any payment received $1,030.61 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Lpch Medical Group Div OF LucilePalo Alto, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Nancy Elizabeth Mason among 5,088 obstetrics & gynecology physician records in California
Nancy Elizabeth Mason, MD is one of 5,088 obstetrics & gynecology physician records with a practice address in California. 74% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 48% of them.
- NPI issued2007 · 48% of these records are older, 38% newer
- In a Medicare fileYes · 74% of these records are
- In the CMS Doctors and Clinicians fileYes · 53% of these records are
- Graduated1977 · median 2004 among the 2,700 with a school on file
- Record last updated2007 · 64% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207V00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Obstetrics & Gynecology Physician providers in California
There are 5,088 obstetrics & gynecology physician records in California.
All 5,088 in California → Every provider in Palo Alto → Obstetrics & Gynecology Physician nationwide →
The 8 obstetrics & gynecology physician records with the nearest ZIP codes
- Alireza Abdollah Shamshirsaz, M.D.Palo Alto, CA 943041881804235
- Erika Balassiano, MDPalo Alto, CA 943041558599928
- Virginia Chan, D.O.Palo Alto, CA 943041134329972
- Edward Cohen, MDPalo Alto, CA 943041003838541
- Lisa Goldthwaite, M.D.Palo Alto, CA 943041457594244
- Betty Kung, MDPalo Alto, CA 943041972675700
- Kathryn Lannin, MDPalo Alto, CA 943041508951583
- Madeleine Lemyre, M.D.Palo Alto, CA 943041831389097
Common questions
What is Nancy Elizabeth Mason, MD's NPI number?
Nancy Elizabeth Mason, MD's National Provider Identifier (NPI) is 1649312067, issued on Feb 13, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Nancy Elizabeth Mason, MD located?
The NPPES record lists a practice address at 1101 Welch RD, Palo Alto, CA, 94304. Phone: (650) 329-1293. Providers update this record themselves, so call before visiting.
How can I verify Nancy Elizabeth Mason, MD's license?
NPPES lists California license number G38836, 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 Nancy Elizabeth Mason, MD prescribe under Medicare Part D?
In 2024, Nancy Elizabeth Mason, MD had 48 Medicare Part D claims for 14 beneficiaries; the average among obstetrics & gynecology physician prescribers was 165. Part D covers Medicare prescriptions only.
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.