Doctor profile · Federal record

Dr. Fidel Castillo Diaz, MD

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

  • NPI 1689667347
  • Accepts Medicare
  • MIPS 77.1 / 100 · 2023
  • 28 yrs in practice
  • Male
  • Solo practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
840 S Wood St, M-C 717 Csn 440
Chicago, IL 606124325
(312) 996-7704
fax (312) 413-8283

Credentials & registration

NPPES · NUCC
NPI registered
August 2005 — 21 yrs on file
Profile last updated
March 5, 2014
Year of graduation
1998 — 28 yrs since
Specialty taxonomy
207RG0300X — NUCC code
State license (1)
Illinois #036124066

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1689667347. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
161
Distinct HCPCS
5
Medicare allowed
$10,777
HCPCS Description Services Patients Avg allowed
99214 Established patient office or other outpatient visit, 30-39 minutes 66 31 $134
36415 Insertion of needle into vein for collection of blood sample 39 22 $8
83036 Hemoglobin a1c level 31 15 $10
G0008 Administration of influenza virus vaccine 13 13 $30
90694 Influenza vaccine, quadrivalent inactivated, 0.5 ml dosage 12 12 $75

In context: peer comparison

Among 17 peers in Chicago Geriatric Medicine (Internal Medicine) Physician, average services per provider: 88. This provider delivers 1.8× the peer median.

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
375
Patients
62
Total drug cost
$16,992
Drug Type Claims Patients Total cost
Amlodipine Besylate Generic 45 14 $637
Losartan Potassium Generic 38 12 $612
Metformin Hcl Generic 37 13 $571
Levothyroxine Sodium Generic 36 0 $888
Lisinopril Generic 34 12 $423
Omeprazole Generic 29 0 $371
Atorvastatin Calcium Generic 25 11 $517
Albuterol Sulfate Hfa (Albuterol Sulfate) Brand 22 0 $801
Gabapentin Generic 20 0 $340
Tamsulosin Hcl Generic 16 0 $619

Frequently asked questions

Auto-generated from federal data
What is Dr. Fidel Castillo Diaz's medical specialty?
Dr. Fidel Castillo Diaz practices Geriatric Medicine (Internal Medicine) Physician in Chicago, IL.
Where does Dr. Fidel Castillo Diaz practice?
Dr. Fidel Castillo Diaz practices at 840 S Wood St, Chicago, IL 606124325. Office phone: 3129967704.
What is Dr. Fidel Castillo Diaz's NPI?
Dr. Fidel Castillo Diaz's National Provider Identifier (NPI) is 1689667347, issued by NPPES.
Does Dr. Fidel Castillo Diaz accept Medicare assignment?
Yes. Dr. Fidel Castillo Diaz accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Fidel Castillo Diaz commonly perform?
Top Medicare-reported procedures in 2023: Established patient office or other outpatient visit (HCPCS 99214); Insertion of needle into vein for collection of blood sample (HCPCS 36415); Hemoglobin a1c level (HCPCS 83036). Source: CMS Medicare Physician & Other Practitioners file.