Stephen Parnell Ma, MD
Internal Medicine Physician · Stanford, CA
Stephen Parnell Ma, MD is an internal medicine physician with a practice address in Stanford, California, and NPI 1508329442, issued on Apr 8, 2019. Check the license (California A177624, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Stephen Parnell Ma
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A177624 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 8, 2019
- Record last updated
- Jul 8, 2024
- Medicare enrollment
- Enrolled (PECOS I20240306000795); accepts Medicare assignment
- Entity
- Type 1 · individual
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Verify Stephen Parnell Ma in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A177624Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
One hospital affiliation
- 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.
Stephen Parnell Ma among 17,696 internal medicine physician records in California
Stephen Parnell Ma, MD is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2019, is newer than 86% of them.
- NPI issued2019 · 86% of these records are older, 11% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2019 · median 2004 among the 11,065 with a school on file
- Record last updated2024 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
378 internal medicine physician records list a practice address in Stanford
They are 378 of the 5,606 NPPES records with a practice address in Stanford, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Stanford → Internal Medicine Physician nationwide →
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Common questions
What is Stephen Parnell Ma, MD's NPI number?
Stephen Parnell Ma, MD's National Provider Identifier (NPI) is 1508329442, issued on Apr 8, 2019. An NPI identifies a provider in billing; it is not a license.
Where is Stephen Parnell Ma, 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 Stephen Parnell Ma, MD's license?
NPPES lists California license number A177624, 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.
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.