Alex Diaz, D.O.
Pulmonary Disease Physician · San Ramon, CA
Alex Diaz, D.O. is a pulmonary disease physician with a practice address in San Ramon, California, and NPI 1659759363, issued on May 13, 2015. Check the license (California 20A18649, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Alex Diaz
- Credential
- D.O.
- Primary taxonomy
- Pulmonary Disease Physician 207RP1001X
- License number
- 20A18649 CA
Self-reported in NPPES; status is on the state search - Practice location
- 5401 Norris Canyon RD Ste 306, San Ramon, CA 94583
- Phone
- (925) 866-8822
- Enumerated
- May 13, 2015
- Record last updated
- Sep 8, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicaid ID
- 1659759363 CO
- Medicare enrollment
- Enrolled (PECOS I20210921000801); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest pulmonary disease physician records → All 1,443 in California → Look up another NPI →
Verify Alex Diaz in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A18649Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
12% fewer Medicare Part D claims than the average pulmonary disease physician in 2024
1,257 Medicare Part D claims for 210 beneficiaries, against an average of 1,425 among the 11,596 providers of this specialty who prescribed in Part D. 23 claims were for opioids.
Most prescribed
- Trelegy Ellipta113 claims
- Montelukast Sodium65 claims
- Albuterol Sulfate Hfa63 claims
- Prednisone58 claims
- Wixela Inhub56 claims
- Breztri Aerosphere48 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: $1,485.57
63 payments; by number, the most common kind was food and beverage; the largest payer was GlaxoSmithKline, LLC. The 8,806 providers of this specialty with any payment received $5,159.88 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.
Alex Diaz among 1,443 pulmonary disease physician records in California
Alex Diaz, D.O. is one of 1,443 pulmonary disease physician records with a practice address in California. 84% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2015, is newer than 83% of them.
- NPI issued2015 · 83% of these records are older, 14% newer
- In a Medicare fileYes · 84% of these records are
- In the CMS Doctors and Clinicians fileYes · 74% of these records are
- Graduated2015 · median 2002 among the 1,061 with a school on file
- Record last updated2021 · 55% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RP1001X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Pulmonary Disease Physician providers in California
There are 1,443 pulmonary disease physician records in California.
All 1,443 in California → Every provider in San Ramon → Pulmonary Disease Physician nationwide →
The 8 pulmonary disease physician records with the nearest ZIP codes
- Anitha Angan, MDSan Ramon, CA 945831528261500
- Veena Dronamraju, MDPleasanton, CA 945881861856783
- Jerrold Kram, M.D.San Leandro, CA 945781205922093
- Tracey Liu, MDPleasanton, CA 945881639639693
- John Ruddy, M.D.San Leandro, CA 945781902890130
- Bill Wong, MDPleasanton, CA 945881477553444
- John Yee, MDPleasanton, CA 945881497755466
- Sherfong Gee, D.O.San Leandro, CA 945771639274772
Common questions
What is Alex Diaz, D.O.'s NPI number?
Alex Diaz, D.O.'s National Provider Identifier (NPI) is 1659759363, issued on May 13, 2015. An NPI identifies a provider in billing; it is not a license.
Where is Alex Diaz, D.O. located?
The NPPES record lists a practice address at 5401 Norris Canyon RD Ste 306, San Ramon, CA, 94583. Phone: (925) 866-8822. Providers update this record themselves, so call before visiting.
How can I verify Alex Diaz, D.O.'s license?
NPPES lists California license number 20A18649, 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 Alex Diaz, D.O. prescribe under Medicare Part D?
In 2024, Alex Diaz, D.O. had 1,257 Medicare Part D claims for 210 beneficiaries; the average among pulmonary disease physician prescribers was 1,425. 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.