Irene S. Tan, M.D.
Obstetrics & Gynecology Physician · Simi Valley, CA
Irene S. Tan, M.D. is an obstetrics & gynecology physician with a practice address in Simi Valley, California, and NPI 1699942425, issued on May 12, 2008. Check the license on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Irene S. Tan
- Credential
- M.D.
- Primary taxonomy
- Obstetrics & Gynecology Physician 207V00000X
- Practice location
- 1147 Red Tail Way, Simi Valley, CA 93065
- Phone
- (805) 527-8055
- Enumerated
- May 12, 2008
- Record last updated
- Jun 27, 2012 (not updated in 14 years: call before relying on the address or phone)
- Fax
- (805) 520-8849
- Medicare enrollment
- Enrolled (PECOS I20090810000043); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest obstetrics & gynecology physician records → All 5,088 in California → Look up another NPI →
Also registered at 1147 Red Tail Way
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Brittney Ayers, NURSE PRACTITIONERFamily Nurse Practitioner1114454816
- Sarah Garcia, D.O.Obstetrics & Gynecology Physician1790088714
- Catherine Kim, MDObstetrics & Gynecology Physician1972596120
- John Koh, MDObstetrics & Gynecology Physician1841283009
- Ga Lee, M.D.Obstetrics & Gynecology Physician1497918254
- Jennifer Lee, D.O.Obstetrics & Gynecology Physician1033502869
Verify Irene S. Tan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of CaliforniaCheck the board
- 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
16% fewer Medicare Part D claims than the average obstetrics & gynecology physician in 2024
138 Medicare Part D claims for 42 beneficiaries, against an average of 165 among the 28,733 providers of this specialty who prescribed in Part D.
Most prescribed
- Estradiol47 claims
- Valacyclovir16 claims
- Progesterone14 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: $330.08
13 payments; by number, the most common kind was food and beverage; the largest payer was Sage Therapeutics, Inc. The 21,429 providers of this specialty with any payment received $1,030.61 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.
Bills Medicare through one group practice
- Simi Obstetrics And Gynecology Medical Group A Medical CorpSimi Valley, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Irene S. Tan among 5,088 obstetrics & gynecology physician records in California
Irene S. Tan, M.D. is one of 5,088 obstetrics & gynecology physician records with a practice address in California. 74% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2008, is newer than 62% of them.
- NPI issued2008 · 62% of these records are older, 34% newer
- In a Medicare fileYes · 74% of these records are
- In the CMS Doctors and Clinicians fileYes · 53% of these records are
- Graduated2004 · median 2004 among the 2,700 with a school on file
- Record last updated2012 · 64% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207V00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Obstetrics & Gynecology Physician providers in California
There are 5,088 obstetrics & gynecology physician records in California.
All 5,088 in California → Every provider in Simi Valley → Obstetrics & Gynecology Physician nationwide →
The 8 obstetrics & gynecology physician records with the nearest ZIP codes
- Sarah Garcia, D.O.Simi Valley, CA 930651790088714
- Catherine Kim, MDSimi Valley, CA 930651972596120
- John Koh, MDSimi Valley, CA 930651841283009
- Ga Lee, M.D.Simi Valley, CA 930651497918254
- Jennifer Lee, D.O.Simi Valley, CA 930651033502869
- Gerald Murphy, MDSimi Valley, CA 930651023001286
- Abigail NimzSimi Valley, CA 930651750736260
- Roopa Rao-Karlamangla, M.D.Simi Valley, CA 930651588650865
Common questions
What is Irene S. Tan, M.D.'s NPI number?
Irene S. Tan, M.D.'s National Provider Identifier (NPI) is 1699942425, issued on May 12, 2008. An NPI identifies a provider in billing; it is not a license.
Where is Irene S. Tan, M.D. located?
The NPPES record lists a practice address at 1147 Red Tail Way, Simi Valley, CA, 93065. Phone: (805) 527-8055. Providers update this record themselves, so call before visiting.
How can I verify Irene S. Tan, M.D.'s license?
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 Irene S. Tan, M.D. prescribe under Medicare Part D?
In 2024, Irene S. Tan, M.D. had 138 Medicare Part D claims for 42 beneficiaries; the average among obstetrics & gynecology physician prescribers was 165. 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.