Doctor profile · Federal record

Dr. John Riordan, MD

Specialist (CMS: Nephrology) · San Francisco, CA

  • NPI 1619040227
  • Accepts Medicare
  • MIPS 82.8 / 100 · 2023
  • 39 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
2100 Webster St, Suite 320
San Francisco, CA 941152377
(415) 923-3815
fax (415) 749-5713

Credentials & registration

NPPES · NUCC
NPI registered
November 2006 — 20 yrs on file
Profile last updated
July 29, 2022
Year of graduation
1987 — 39 yrs since
Specialty taxonomy
174400000X — NUCC code
State license (1)
California #A52155
Medicaid
CA #00A521550

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1619040227. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
1,429
Distinct HCPCS
10
Medicare allowed
$237,160
HCPCS Description Services Patients Avg allowed
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 601 173 $135
99214 Established patient office or other outpatient visit, 30-39 minutes 407 170 $152
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 110 99 $196
90961 Dialysis services, 2-3 physician visits per month (20 years or older) 91 21 $339
90960 Dialysis services, 4 or more physician visits per month (20 years or older) 47 16 $406
99213 Established patient office or other outpatient visit, 20-29 minutes 46 38 $109
99443 Telephone medical discussion with physician, 21-30 minutes 38 26 $153
90962 Dialysis services, 1 physician visit per month (20 years or older) 32 13 $236
81000 Manual urinalysis test with examination using microscope, non-automated 28 26 $4
99204 New patient office or other outpatient visit, 45-59 minutes 16 16 $197

In context: peer comparison

Among 10 peers in San Francisco Specialist, average services per provider: 612. This provider delivers 2.3× the peer median.

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
986
Patients
270
Total drug cost
$309,944
Drug Type Claims Patients Total cost
Losartan Potassium Generic 173 53 $2,656
Amlodipine Besylate Generic 146 49 $1,814
Farxiga (Dapagliflozin Propanediol) Brand 105 20 $124,992
Jardiance (Empagliflozin) Brand 81 21 $128,403
Lisinopril Generic 74 23 $790
Sevelamer Carbonate Generic 57 20 $23,230
Furosemide Generic 56 23 $503
Calcitriol Generic 49 16 $1,573
Cinacalcet Hcl Generic 42 0 $17,286
Hydrochlorothiazide Generic 38 11 $201

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. John Riordan's medical specialty?
Dr. John Riordan practices Specialist in San Francisco, CA.
Where does Dr. John Riordan practice?
Dr. John Riordan practices at 2100 Webster St, San Francisco, CA 941152377. Office phone: 4159233815.
What is Dr. John Riordan's NPI?
Dr. John Riordan's National Provider Identifier (NPI) is 1619040227, issued by NPPES.
Does Dr. John Riordan accept Medicare assignment?
Yes. Dr. John Riordan accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. John Riordan commonly perform?
Top Medicare-reported procedures in 2023: Subsequent hospital care with moderate levelof medical decision making (HCPCS 99233); Established patient office or other outpatient visit (HCPCS 99214); Initial hospital care with moderate level of medical decision making (HCPCS 99223). Source: CMS Medicare Physician & Other Practitioners file.