Robert Siew, M.D.
NPI 1578539516 · Internal Medicine Physician · Pasadena, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Robert Siew, M.D. is a Internal Medicine Physician provider in Pasadena, CA (NPI 1578539516).
Provider details
- NPI number
- 1578539516
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- A45333 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
20 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
3,643 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 2,441 | $77 |
| Hospital Discharge Day Management, 30 Minutes Or Less99238 | 556 | $80 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 535 | $170 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 111 | $95 |
Typical Medicare-allowed amounts for these services range $77–$170 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 53 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Apixabanbrand: Eliquis | 160 | 49 |
| Atorvastatin Calcium | 138 | 49 |
| Amlodipine Besylate | 125 | 42 |
| Lisinopril | 76 | 17 |
| Carvedilol | 75 | 35 |
| Metoprolol Succinate | 64 | 32 |
| Pantoprazole Sodium |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$338 across 10 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-02-28
- Last updated
- 2022-10-13
- Certified
- 2022-10-13
Frequently asked questions
- What is Robert Siew's NPI number?
- Robert Siew's National Provider Identifier (NPI) is 1578539516, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Robert Siew's specialty?
- Robert Siew is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Robert Siew located?
- Robert Siew's practice location on file with NPPES is 10 Congress St Ste 155, Pasadena, CA 91105-3027.
- What is Robert Siew's phone number?
- The practice phone number listed in the NPPES registry for Robert Siew is (626) 521-5331.
- Does Robert Siew accept Medicare?
- Robert Siew is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Robert Siew's NPI active?
- Yes — Robert Siew's NPI (1578539516) is active in the NPPES registry as of the last update on 2022-10-13.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.