Nancy Chiao-Castle
Nurse Practitioner · San Mateo, CA
Nancy Chiao-Castle is a nurse practitioner with a practice address in San Mateo, California, and NPI 1578619052, issued on Jan 26, 2007. Check the license (California RN245686, as entered in NPPES) with the California board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Nancy Chiao-Castle
- Primary taxonomy
- Nurse Practitioner 363L00000X
- License number
- RN245686 CA
Self-reported in NPPES; status is on the state search - Practice location
- 222 W 39TH Ave, San Mateo, CA 94403
- Phone
- (650) 573-2222
- Enumerated
- Jan 26, 2007
- Record last updated
- Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20040507001254); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest nurse practitioner records → All 8,223 in California → Look up another NPI →
Also registered at 222 W 39TH Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Zohra Ansari, MSWClinical Social Worker1326462904
Verify Nancy Chiao-Castle in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich California board licenses this profession
Search for license RN245686Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
46% fewer Medicare Part D claims than the average nurse practitioner in 2024
594 Medicare Part D claims for 185 beneficiaries, against an average of 1,109 among the 54,319 providers of this specialty who prescribed in Part D.
Most prescribed
- Amlodipine Besylate51 claims
- Atorvastatin Calcium43 claims
- Diclofenac Sodium40 claims
- Losartan Potassium33 claims
- Albuterol Sulfate Hfa28 claims
- Metformin Hcl19 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.
Bills Medicare through one group practice
- County OF San MateoSan Mateo, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Nancy Chiao-Castle among 8,223 nurse practitioner records in California
Nancy Chiao-Castle is one of 8,223 nurse practitioner records with a practice address in California. 65% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 18% of them.
- NPI issued2007 · 18% of these records are older, 73% newer
- In a Medicare fileYes · 65% of these records are
- In the CMS Doctors and Clinicians fileYes · 42% of these records are
- Graduated1999 · median 2017 among the 3,425 with a school on file
- Record last updated2007 · 45% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363L00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Nurse Practitioner providers in California
There are 8,223 nurse practitioner records in California.
All 8,223 in California → Every provider in San Mateo → Nurse Practitioner nationwide →
The 8 nurse practitioner records with the nearest ZIP codes
- Stacey Adelson, NPSan Mateo, CA 944031104951797
- Faina Birman, NPSan Mateo, CA 944031730242249
- Barbara Brodie, NPSan Mateo, CA 944031124192893
- Tracy ButlerSan Mateo, CA 944031457407199
- Maria Cruz, NPSan Mateo, CA 944031861568768
- Maia DehlingerSan Mateo, CA 944031285706390
- Wendee Duhon, NPSan Mateo, CA 944031134299605
- Frances EplerSan Mateo, CA 944031609922186
Common questions
What is Nancy Chiao-Castle's NPI number?
Nancy Chiao-Castle's National Provider Identifier (NPI) is 1578619052, issued on Jan 26, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Nancy Chiao-Castle located?
The NPPES record lists a practice address at 222 W 39TH Ave, San Mateo, CA, 94403. Phone: (650) 573-2222. Providers update this record themselves, so call before visiting.
How can I verify Nancy Chiao-Castle's license?
NPPES lists California license number RN245686, as entered by the provider. Search the California board that licenses this profession; the NPPES record confirms identity only.
How much does Nancy Chiao-Castle prescribe under Medicare Part D?
In 2024, Nancy Chiao-Castle had 594 Medicare Part D claims for 185 beneficiaries; the average among nurse practitioner prescribers was 1,109. 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.