Jay A. Keystone, M.D.
Allergy & Immunology (Internal Medicine) Physician · Vacaville, CA
Jay A. Keystone, M.D. is an allergy & immunology (internal medicine) physician with a practice address in Vacaville, California, and NPI 1306115001, issued on Dec 26, 2011. Check the license (California C29865, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Jay A. Keystone
- Credential
- M.D.
- Primary taxonomy
- Allergy & Immunology (Internal Medicine) Physician 207RA0201X
- License number
- C29865 CA
Self-reported in NPPES; status is on the state search - Practice location
- 365 Evergreen Dr, Vacaville, CA 95688
- Phone
- (707) 446-8581
- Enumerated
- Dec 26, 2011
- Record last updated
- Apr 9, 2020 (not updated in 6 years: call before relying on the address or phone)
- Fax
- (707) 446-8581
- Medicare enrollment
- Enrolled (PECOS I20181221001193); may accept Medicare assignment
- Medical or professional school
- University Of Michigan Medical School, 1970
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest allergy & immunology (internal medicine) physician records → All 81 in California → Look up another NPI →
Verify Jay A. Keystone in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license C29865Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
83% fewer Medicare Part D claims than the average allergy & immunology (internal medicine) physician in 2024
138 Medicare Part D claims for 30 beneficiaries, against an average of 789 among the 429 providers of this specialty who prescribed in Part D.
Most prescribed
- Fluticasone-Salmeterol12 claims
- Lisinopril12 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.
Jay A. Keystone among 81 allergy & immunology (internal medicine) physician records in California
Jay A. Keystone, M.D. is one of 81 allergy & immunology (internal medicine) physician records with a practice address in California. 67% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2011, is newer than 53% of them.
- NPI issued2011 · 53% of these records are older, 41% newer
- In a Medicare fileYes · 67% of these records are
- In the CMS Doctors and Clinicians fileYes · 57% of these records are
- Graduated1970 · median 2010 among the 46 with a school on file
- Record last updated2020 · 49% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RA0201X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Allergy & Immunology (Internal Medicine) Physician providers in California
There are 81 allergy & immunology (internal medicine) physician records in California.
All 81 in California → Every provider in Vacaville → Allergy & Immunology (Internal Medicine) Physician nationwide →
The 8 allergy & immunology (internal medicine) physician records with the nearest ZIP codes
- Bruce Ryhal, MDRoseville, CA 956781902812795
- Rosemary Hallett, M.D.Davis, CA 956161376527804
- Aminaa SiddiqiDavis, CA 956161619363314
- Suzanne Teuber, M.D.Davis, CA 956161619950516
- Fatima Ali, MDSacramento, CA 958171093045023
- Anna CherianSacramento, CA 958171215672738
- Stephen Nagy, MDSacramento, CA 958191013929967
- Christine LicataSacramento, CA 958251437619533
Common questions
What is Jay A. Keystone, M.D.'s NPI number?
Jay A. Keystone, M.D.'s National Provider Identifier (NPI) is 1306115001, issued on Dec 26, 2011. An NPI identifies a provider in billing; it is not a license.
Where is Jay A. Keystone, M.D. located?
The NPPES record lists a practice address at 365 Evergreen Dr, Vacaville, CA, 95688. Phone: (707) 446-8581. Providers update this record themselves, so call before visiting.
How can I verify Jay A. Keystone, M.D.'s license?
NPPES lists California license number C29865, 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 Jay A. Keystone, M.D. prescribe under Medicare Part D?
In 2024, Jay A. Keystone, M.D. had 138 Medicare Part D claims for 30 beneficiaries; the average among allergy & immunology (internal medicine) physician prescribers was 789. 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.