Doctor profile · Federal record

Dr. Siddharth Tambar, MD

Rheumatology Physician (CMS: Rheumatology) · Internal Medicine Physician · Chicago, IL

  • NPI 1477655488
  • Accepts Medicare
  • 25 yrs in practice
  • Male
  • Solo practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
618 W Fulton St
Chicago, IL 606611144
(773) 348-7171
fax (737) 348-7414

Credentials & registration

NPPES · NUCC
NPI registered
September 2006 — 20 yrs on file
Profile last updated
February 25, 2026
Year of graduation
2001 — 25 yrs since
Specialty taxonomy
207RR0500X — NUCC code
State license (1)
Illinois #036-111655

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1477655488. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
12,174
Distinct HCPCS
9
Medicare allowed
$216,196
HCPCS Description Services Patients Avg allowed
J1602 Injection, golimumab, 1 mg, for intravenous use 11,600 11 $13
99213 Established patient office or other outpatient visit, 20-29 minutes 152 69 $93
99214 Established patient office or other outpatient visit, 30-39 minutes 150 67 $131
76881 Complete ultrasound scan of joint 107 61 $56
96413 Administration of chemotherapy into vein, 1 hour or less 86 15 $136
99204 New patient office or other outpatient visit, 45-59 minutes 33 33 $171
99442 Telephone medical discussion with physician, 11-20 minutes 18 13 $94
99205 New patient office or other outpatient visit, 60-74 minutes 15 15 $232
J1030 Injection, methylprednisolone acetate, 40 mg 13 12 $8

In context: peer comparison

Among 36 peers in Chicago Rheumatology Physician, average services per provider: 1,230. This provider delivers 9.9× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$683
Transactions
26
Manufacturers
8
Payer (manufacturer) Industry Txns Amount
Alexion Pharmaceuticals, INC. 8 $206.82
Amgen INC. 4 $91.46
Genzyme Corporation 3 $84.09
Pfizer INC. 3 $76.94
Novartis Pharmaceuticals Corporation 2 $66.40
Abbvie INC. 2 $58.78
Ucb, INC. 2 $56.39
GlaxoSmithKline, LLC. 2 $41.97

By nature of payment

Food and Beverage
$683

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
132
Patients
38
Total drug cost
$126,392
Drug Type Claims Patients Total cost
Methotrexate (Methotrexate Sodium) Brand 30 14 $1,717
Hydroxychloroquine Sulfate Generic 25 13 $1,160
Leflunomide Generic 22 0 $2,759
Prednisone Generic 22 11 $95
Actemra (Tocilizumab) Brand 11 0 $45,289
Benlysta (Belimumab) Brand 11 0 $74,215
Sulfasalazine Dr (Sulfasalazine) Brand 11 0 $1,157

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. Siddharth Tambar's medical specialty?
Dr. Siddharth Tambar practices Rheumatology Physician in Chicago, IL.
Where does Dr. Siddharth Tambar practice?
Dr. Siddharth Tambar practices at 618 W Fulton St, Chicago, IL 606611144. Office phone: 7733487171.
What is Dr. Siddharth Tambar's NPI?
Dr. Siddharth Tambar's National Provider Identifier (NPI) is 1477655488, issued by NPPES.
Does Dr. Siddharth Tambar accept Medicare assignment?
Yes. Dr. Siddharth Tambar accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Siddharth Tambar commonly perform?
Top Medicare-reported procedures in 2023: Injection, golimumab, 1 mg, for intravenous use (HCPCS J1602); Established patient office or other outpatient visit (HCPCS 99213); Established patient office or other outpatient visit (HCPCS 99214). Source: CMS Medicare Physician & Other Practitioners file.