John Sierocki, M.D.
NPI 1487792354 · Medical Oncology Physician · Princeton, NJ
Enrolled with Medicare as Practitioner - Medical Oncology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Sierocki, M.D. is a Medical Oncology Physician provider in Princeton, NJ (NPI 1487792354).
Provider details
- NPI number
- 1487792354
- Entity type
- Individual
- Primary specialty
- Medical Oncology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 25MA03428100 (NJ)
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
19 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
15,615 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) |
|---|---|---|
| Insertion of Needle Into Vein for Collection of Blood Sample36415 | 1,695 | $9 |
| Complete Blood Cell Count (red Cells, White Blood Cell, Platelets), Automated Test and Automated Differential White Blood Cell Count85025 | 1,646 | $8 |
| Blood Test, Comprehensive Group of Blood Chemicals80053 | 1,612 | $10 |
| Lactate Dehydrogenase (enzyme) Level83615 | 1,600 | $6 |
| Ferritin (blood Protein) Level82728 | 1,573 | $13 |
| Blood Test, Thyroid Stimulating Hormone (tsh)84443 | 1,552 | $16 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 69 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Levothyroxine Sodium | 183 | 54 |
| Pantoprazole Sodium | 133 | 43 |
| Letrozole | 88 | 26 |
| Omeprazole | 87 | 21 |
| Amlodipine Besylate | 81 | 23 |
| Losartan Potassium | 72 | 19 |
| Atorvastatin Calcium | 70 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$90 across 1 record (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
- 2007-02-02
- Last updated
- 2008-05-16
Frequently asked questions
- What is John Sierocki's NPI number?
- John Sierocki's National Provider Identifier (NPI) is 1487792354, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Sierocki's specialty?
- John Sierocki is listed in the NPPES registry with a primary specialty of Medical Oncology Physician (Allopathic & Osteopathic Physicians).
- Where is John Sierocki located?
- John Sierocki's practice location on file with NPPES is 419 N Harrison St, Princeton, NJ 08540-3521.
- What is John Sierocki's phone number?
- The practice phone number listed in the NPPES registry for John Sierocki is (609) 924-9300.
- Does John Sierocki accept Medicare?
- John Sierocki is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Sierocki's NPI active?
- Yes — John Sierocki's NPI (1487792354) is active in the NPPES registry as of the last update on 2008-05-16.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.