Robert Siew, M.D.
Internal Medicine Physician · Pasadena, CA
Robert Siew, M.D. is an internal medicine physician with a practice address in Pasadena, California, and NPI 1578539516, issued on Feb 28, 2006. Check the license (California A45333, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Robert Siew
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A45333 CA
Self-reported in NPPES; status is on the state search - Practice location
- 10 Congress St Ste 155, Pasadena, CA 91105
- Phone
- (626) 521-5331
- Enumerated
- Feb 28, 2006
- Record last updated
- Oct 13, 2022
- Fax
- (626) 486-0181
- Medicaid ID
- 00A453330 CA
- Medicare enrollment
- Enrolled (PECOS I20100322000665); accepts Medicare assignment
- Medical or professional school
- Tulane University School Of Medicine, 1986
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 10 Congress St Ste 155
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Robert Siew in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A45333Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
25% fewer Medicare Part D claims than the average internal medicine physician in 2024
2,367 Medicare Part D claims for 471 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. 24 claims were for opioids.
Most prescribed
- Eliquis160 claims
- Atorvastatin Calcium138 claims
- Amlodipine Besylate125 claims
- Lisinopril76 claims
- Carvedilol75 claims
- Metoprolol Succinate64 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.
The MIPS final score for 2023 (Medicare payment program): 40.9 of 100
The Merit-based Incentive Payment System score is reported for this clinician. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $337.82
10 payments; by number, the most common kind was food and beverage; the largest payer was Teleflex LLC. 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.
Robert Siew among 17,696 internal medicine physician records in California
Robert Siew, M.D. 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 fileYes · 63% of these records are
- Graduated1986 · median 2004 among the 11,065 with a school on file
- Record last updated2022 · 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).
137 internal medicine physician records list a practice address in Pasadena
They are 137 of the 10,525 NPPES records with a practice address in Pasadena, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Pasadena → Internal Medicine Physician nationwide →
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- George Jung, MDPasadena, CA 911051720051881
- Kristin Karlyn, MDPasadena, CA 911051033182530
- Malathi Narayan, MDPasadena, CA 911051588637466
Common questions
What is Robert Siew, M.D.'s NPI number?
Robert Siew, M.D.'s National Provider Identifier (NPI) is 1578539516, issued on Feb 28, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Robert Siew, M.D. located?
The NPPES record lists a practice address at 10 Congress St Ste 155, Pasadena, CA, 91105. Phone: (626) 521-5331. Providers update this record themselves, so call before visiting.
How can I verify Robert Siew, M.D.'s license?
NPPES lists California license number A45333, 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 Robert Siew, M.D. prescribe under Medicare Part D?
In 2024, Robert Siew, M.D. had 2,367 Medicare Part D claims for 471 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
What is Robert Siew, M.D.'s MIPS final score?
The 2023 MIPS final score is 40.9 of 100. The average among 454,083 clinicians with a measured score was 83.5.
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.