Mary Grehian Yoo, MD
Internal Medicine Physician · San Diego, CA
Mary Grehian Yoo, MD is an internal medicine physician with a practice address in San Diego, California, and NPI 1609935212, issued on Dec 8, 2006. Check the license (California A84430, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Mary Grehian Yoo
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A84430 CA
Self-reported in NPPES; status is on the state search - Practice location
- 4647 Zion Ave, San Diego, CA 92120
- Phone
- (619) 528-5000
- Enumerated
- Dec 8, 2006
- Record last updated
- Dec 21, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20050923000416); accepts Medicare assignment
- Medical or professional school
- Northwestern University Feinberg Medical School, 2002
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 4647 Zion Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Samy Abdou, MDNeurological Surgery Physician1215085006
- Samvel Abelyan, PHARMDPharmacist1306629928
- Ali Aboutaleb, MDFamily Medicine Physician1821261405
- Patricia Achilly, CNMAdvanced Practice Midwife1932257847
- Linda Adams, PAPhysician Assistant1427174689
- Mette-Margrethe Adkisson, M.D.Emergency Medicine Physician1528288081
Verify Mary Grehian Yoo in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A84430Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
30% more Medicare Part D claims than the average internal medicine physician in 2024
4,122 Medicare Part D claims for 555 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 9% of claims. 197 claims were for opioids.
Most prescribed
- Atorvastatin Calcium369 claims
- Lisinopril185 claims
- Rosuvastatin Calcium172 claims
- Amlodipine Besylate160 claims
- Levothyroxine Sodium160 claims
- Losartan Potassium133 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.
Bills Medicare through one group practice
- Southern California Permanente Medical GroupSan Diego, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Mary Grehian Yoo among 17,696 internal medicine physician records in California
Mary Grehian Yoo, 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 2006, is newer than 5% of them.
- NPI issued2006 · 5% of these records are older, 56% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2002 · median 2004 among the 11,065 with a school on file
- Record last updated2021 · 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).
961 internal medicine physician records list a practice address in San Diego
They are 961 of the 52,937 NPPES records with a practice address in San Diego, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in San Diego → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Wilfredo Abesamis, M.D.San Diego, CA 921201992754832
- Kenneth Antons, M.D.San Diego, CA 921201982668182
- David Chang, M.D.San Diego, CA 921201073596342
- Fred Corey, M.D.San Diego, CA 921201912989674
- Elaine Gertser, MDSan Diego, CA 921201992719967
- Joanne Keenan, D.O.San Diego, CA 921201043281074
- Hyunsoo Kim, MDSan Diego, CA 921201598789737
- Murray Kornblit, M.D.San Diego, CA 921201932181682
Common questions
What is Mary Grehian Yoo, MD's NPI number?
Mary Grehian Yoo, MD's National Provider Identifier (NPI) is 1609935212, issued on Dec 8, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mary Grehian Yoo, MD located?
The NPPES record lists a practice address at 4647 Zion Ave, San Diego, CA, 92120. Phone: (619) 528-5000. Providers update this record themselves, so call before visiting.
How can I verify Mary Grehian Yoo, MD's license?
NPPES lists California license number A84430, 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 Mary Grehian Yoo, MD prescribe under Medicare Part D?
In 2024, Mary Grehian Yoo, MD had 4,122 Medicare Part D claims for 555 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.