William Alan Kocsis, MD
Internal Medicine Physician · Napa, CA
William Alan Kocsis, MD is an internal medicine physician with a practice address in Napa, California, and NPI 1225078280, issued on Jun 7, 2006. Check the license (California G48474, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- William Alan Kocsis
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- G48474 CA
Self-reported in NPPES; status is on the state search - Practice location
- 2100 Napa-Vallejo Highway, Napa, CA 94558
- Phone
- (707) 253-5000
- Enumerated
- Jun 7, 2006
- Record last updated
- Jul 13, 2026
- Fax
- (707) 253-5513
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 2100 Napa-Vallejo Highway
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify William Alan Kocsis in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G48474Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Industry payments in 2024: $150.00
1 payment: food and beverage; the largest payer was Celltrion USA Inc. The 50,334 providers of this specialty with any payment received $1,303.06 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.
William Alan Kocsis among 17,696 internal medicine physician records in California
William Alan Kocsis, 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 fileNo · 63% of these records are
- Record last updated2026 · 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).
61 internal medicine physician records list a practice address in Napa
They are 61 of the 3,583 NPPES records with a practice address in Napa, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Napa → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Abhijit Adhye, M.D.Napa, CA 945581992763205
- Scott Anderson, MDNapa, CA 945581619929494
- Patricia Dizmang, M.D.Napa, CA 945581194790261
- Beth Hartung, M.D.Napa, CA 945581275501488
- Ronald Julis, M.D.Napa, CA 945581053311167
- Paul Laband, MDNapa, CA 945581427029040
- Monica McKeever, MDNapa, CA 945581538135298
- Lane Melgarejo, MDNapa, CA 945581588657308
Common questions
What is William Alan Kocsis, MD's NPI number?
William Alan Kocsis, MD's National Provider Identifier (NPI) is 1225078280, issued on Jun 7, 2006. An NPI identifies a provider in billing; it is not a license.
Where is William Alan Kocsis, MD located?
The NPPES record lists a practice address at 2100 Napa-Vallejo Highway, Napa, CA, 94558. Phone: (707) 253-5000. Providers update this record themselves, so call before visiting.
How can I verify William Alan Kocsis, MD's license?
NPPES lists California license number G48474, 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.