Mark Tan, M.D.
NPI 1083770580 · Rheumatology Physician · Smithtown, NY
Enrolled with Medicare as Practitioner - Rheumatology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Tan, M.D. is a Rheumatology Physician provider in Smithtown, NY (NPI 1083770580).
Provider details
- NPI number
- 1083770580
- Entity type
- Individual
- Primary specialty
- Rheumatology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 165674 (NY)
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
3,362 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 | 583 | $9 |
| Established Patient Office Or Other Outpatient Visit With Straightforward Medical Decision Making, If Using Time, 10 Minutes Or More99212 | 525 | $60 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 355 | $136 |
| Injection of Drug Or Substance Into Vein96374 | 313 | $40 |
| Administration of Chemotherapy Into Vein, 1 Hour Or Less96413 | 304 | $142 |
| Aspiration And/Or Injection of Fluid From Large Joint20610 | 301 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 32 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Prednisone | 154 | 78 |
| Tocilizumabbrand: Actemra | 90 | 13 |
| Denosumabbrand: Prolia | 88 | 57 |
| Gabapentin | 82 | 28 |
| Hydroxychloroquine Sulfate | 54 | 12 |
| Upadacitinibbrand: Rinvoq | 46 | — |
| Tofacitinib Citratebrand: Xeljanz Xr |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$3,014 across 142 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
- 2006-12-29
- Last updated
- 2011-07-27
Frequently asked questions
- What is Mark Tan's NPI number?
- Mark Tan's National Provider Identifier (NPI) is 1083770580, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Tan's specialty?
- Mark Tan is listed in the NPPES registry with a primary specialty of Rheumatology Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Tan located?
- Mark Tan's practice location on file with NPPES is 222 Middle Country Road, Smithtown, NY 11787.
- What is Mark Tan's phone number?
- The practice phone number listed in the NPPES registry for Mark Tan is (631) 724-8900.
- Does Mark Tan accept Medicare?
- Mark Tan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Tan's NPI active?
- Yes — Mark Tan's NPI (1083770580) is active in the NPPES registry as of the last update on 2011-07-27.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.