Alejandro Ernesto Diaz, MD
Internal Medicine Physician · Oakland, CA
Alejandro Ernesto Diaz, MD is an internal medicine physician with a practice address in Oakland, California, and NPI 1437591104, issued on Jul 23, 2013. Check the license (California 132627, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Alejandro Ernesto Diaz
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 132627 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1411 E 31St St, Oakland, CA 94602
- Phone
- (510) 437-4887
- Enumerated
- Jul 23, 2013
- Record last updated
- Apr 13, 2016 (not updated in 10 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20151204000660); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 1411 E 31St St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Alejandro Ernesto Diaz in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 132627Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
65% fewer Medicare Part D claims than the average internal medicine physician in 2024
1,120 Medicare Part D claims for 112 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. 50 claims were for opioids.
Most prescribed
- Atorvastatin Calcium109 claims
- Amlodipine Besylate68 claims
- Hydrocodone-Acetaminophen42 claims
- Lisinopril41 claims
- Famotidine33 claims
- Metformin Hcl32 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): 91 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
- Alameda Health SystemOakland, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Alejandro Ernesto Diaz among 17,696 internal medicine physician records in California
Alejandro Ernesto Diaz, 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 2013, is newer than 71% of them.
- NPI issued2013 · 71% of these records are older, 26% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2012 · median 2004 among the 11,065 with a school on file
- Record last updated2016 · 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).
432 internal medicine physician records list a practice address in Oakland
They are 432 of the 18,558 NPPES records with a practice address in Oakland, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Oakland → Internal Medicine Physician nationwide →
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- Annemarie Mallick, D.O.Oakland, CA 946021588633507
Common questions
What is Alejandro Ernesto Diaz, MD's NPI number?
Alejandro Ernesto Diaz, MD's National Provider Identifier (NPI) is 1437591104, issued on Jul 23, 2013. An NPI identifies a provider in billing; it is not a license.
Where is Alejandro Ernesto Diaz, MD located?
The NPPES record lists a practice address at 1411 E 31St St, Oakland, CA, 94602. Phone: (510) 437-4887. Providers update this record themselves, so call before visiting.
How can I verify Alejandro Ernesto Diaz, MD's license?
NPPES lists California license number 132627, 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 Alejandro Ernesto Diaz, MD prescribe under Medicare Part D?
In 2024, Alejandro Ernesto Diaz, MD had 1,120 Medicare Part D claims for 112 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
What is Alejandro Ernesto Diaz, MD's MIPS final score?
The 2023 MIPS final score is 91 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.