Guillermo Perez, P.A.
Physician Assistant · Greenfield, CA
Guillermo Perez, P.A. is a physician assistant with a practice address in Greenfield, California, and NPI 1275557506, issued on Jul 27, 2006. Check the license (California PA18456, as entered in NPPES) with the California board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Guillermo Perez
- Credential
- P.A.
- Primary taxonomy
- Physician Assistant 363A00000X
- License number
- PA18456 CA
Self-reported in NPPES; status is on the state search - Practice location
- 467 EL Camino Real, Greenfield, CA 93927
- Phone
- (831) 674-0112
- Enumerated
- Jul 27, 2006
- Record last updated
- Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
- Fax
- (831) 674-4199
- Medicare enrollment
- Enrolled (PECOS I20060822000466); may accept Medicare assignment
- Entity
- Type 1 · individual
Also registered at 467 EL Camino Real
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Alejandra Beristain-Barajas, MDFamily Medicine Physician1114548880
- Crystal Lynette Hernandez, PAMedical Physician Assistant1134959398
Verify Guillermo Perez in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich California board licenses this profession
Search for license PA18456Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
89% fewer Medicare Part D claims than the average physician assistant in 2024
94 Medicare Part D claims for 55 beneficiaries, against an average of 830 among the 101,058 providers of this specialty who prescribed in Part D.
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: $33.46
1 payment: food and beverage; the largest payer was Boehringer Ingelheim Pharmaceuticals, Inc. The 64,719 providers of this specialty with any payment received $841.65 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.
One hospital affiliation
- Sutter Coast HospitalCrescent City, CA · Acute Care Hospitals2 of 5 stars
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through); hospitals matched to CMS Hospital General Information (Care Compare) (data.cms.gov). Star ratings are CMS hospital ratings, not ratings of this provider.
2 physician assistant records list a practice address in Greenfield
They are 2 of the 62 NPPES records with a practice address in Greenfield, and 14,451 physician assistant records in California.
All 2 in Greenfield → All 14,451 in California → Every provider in Greenfield →
Other physician assistant records in California
- Marcia -Galbraith, PAStockton, CA1407143274
- Danny Abad, PAOrange, CA1477158673
- Lea Dominique Abadies, PATustin, CA1124754254
- Rea Elizabeth Abaniel, P.A.-CSeal Beach, CA1396173621
- Ramina Abbasi, PA-CSignal Hill, CA1093448300
- Ariel Abbott, PA-CStockton, CA1780334342
- Barrie Abbott, PA-CAnza, CA1861602575
- Elizabeth Abbott, PA-CSan Diego, CA1437540762
- Terri Abbott, P.A.La Jolla, CA1811165566
- Angela Abboud, MMS, PA-CSanta Rosa, CA1114399334
Common questions
What is Guillermo Perez, P.A.'s NPI number?
Guillermo Perez, P.A.'s National Provider Identifier (NPI) is 1275557506, issued on Jul 27, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Guillermo Perez, P.A. located?
The NPPES record lists a practice address at 467 EL Camino Real, Greenfield, CA, 93927. Phone: (831) 674-0112. Providers update this record themselves, so call before visiting.
How can I verify Guillermo Perez, P.A.'s license?
NPPES lists California license number PA18456, as entered by the provider. Search the California board that licenses this profession; the NPPES record confirms identity only.
How much does Guillermo Perez, P.A. prescribe under Medicare Part D?
In 2024, Guillermo Perez, P.A. had 94 Medicare Part D claims for 55 beneficiaries; the average among physician assistant prescribers was 830. 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.