Siddharth Tambar, MD
NPI 1477655488 · Rheumatology Physician · Chicago, IL
Enrolled with Medicare as Dme Supplier - Physician - General Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Provider details
- NPI number
- 1477655488
- Entity type
- Individual
- Primary specialty
- Rheumatology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- Yes
- License
- 036-111655 (IL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
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
886 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) |
|---|---|---|
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 286 | $17 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 215 | $132 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 111 | $94 |
| Complete Ultrasound Scan of Joint76881 | 104 | $55 |
| Administration of Chemotherapy Into Vein, 1 Hour Or Less96413 | 87 | $132 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 8 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Prednisone | 37 | 15 |
| Methotrexate Sodiumbrand: Methotrexate | 29 | 18 |
| Leflunomide | 24 | 12 |
| Belimumabbrand: Benlysta | 23 | — |
| Hydroxychloroquine Sulfate | 18 | 12 |
| Tramadol Hcl | 17 | 11 |
| Diazepam | 13 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$683 across 26 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
- 2006-09-01
- Last updated
- 2026-02-25
- Certified
- 2026-02-25
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.