Doctor profile · Federal record

Dr. Dirk Diefendorf, M.D.

Sports Medicine (Neuromusculoskeletal Medicine) Physician (CMS: Orthopedic Surgery) · San Mateo, CA

  • NPI 1467559443
  • Accepts Medicare
  • MIPS 100.0 / 100 · 2023
  • 43 yrs in practice
  • Male
  • Solo practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
101 S Ellsworth Ave, Suite 607
San Mateo, CA 944013956
(650) 347-0157
fax (650) 347-0566

Credentials & registration

NPPES · NUCC
NPI registered
September 2006 — 20 yrs on file
Profile last updated
August 30, 2010
Year of graduation
1983 — 43 yrs since
Specialty taxonomy
204C00000X — NUCC code
State license (1)
California #G53558

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1467559443. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
521
Distinct HCPCS
4
Medicare allowed
$79,980
HCPCS Description Services Patients Avg allowed
99214 Established patient office or other outpatient visit, 30-39 minutes 290 159 $153
99204 New patient office or other outpatient visit, 45-59 minutes 110 110 $198
99213 Established patient office or other outpatient visit, 20-29 minutes 97 71 $109
99203 New patient office or other outpatient visit, 30-44 minutes 24 24 $134

In context: peer comparison

Among 1 peers in this city , average services per provider: 130. This provider delivers 4.0× the peer median.

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
204
Patients
101
Total drug cost
$1,522
Drug Type Claims Patients Total cost
Meloxicam Generic 125 52 $452
Diclofenac Sodium Generic 27 14 $433
Cephalexin Generic 21 19 $166
Hydrocodone-Acetaminophen (Hydrocodone/Acetaminophen) Brand 18 16 $82
Nabumetone Generic 13 0 $389

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. Dirk Diefendorf's medical specialty?
Dr. Dirk Diefendorf practices Sports Medicine (Neuromusculoskeletal Medicine) Physician in San Mateo, CA.
Where does Dr. Dirk Diefendorf practice?
Dr. Dirk Diefendorf practices at 101 S Ellsworth Ave, San Mateo, CA 944013956. Office phone: 6503470157.
What is Dr. Dirk Diefendorf's NPI?
Dr. Dirk Diefendorf's National Provider Identifier (NPI) is 1467559443, issued by NPPES.
Does Dr. Dirk Diefendorf accept Medicare assignment?
Yes. Dr. Dirk Diefendorf accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Dirk Diefendorf commonly perform?
Top Medicare-reported procedures in 2023: Established patient office or other outpatient visit (HCPCS 99214); New patient office or other outpatient visit (HCPCS 99204); Established patient office or other outpatient visit (HCPCS 99213). Source: CMS Medicare Physician & Other Practitioners file.