Doctor profile · Federal record

Dr. Spencer Mares, FNP-C, AGACNP-BC

Acute Care Nurse Practitioner (CMS: Nurse Practitioner) · Family Nurse Practitioner · Family Nurse Practitioner · Lake Saint Louis, MO

  • NPI 1437667490
  • Accepts Medicare
  • 9 yrs in practice
  • Licensed in 2 states
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
100 Medical Plz
Lake Saint Louis, MO 633671366
(636) 625-5200
Mailing address
50 Meadow Run CT
Saint Peters, MO 633035805

Credentials & registration

NPPES · NUCC
NPI registered
January 2018 — 8 yrs on file
Profile last updated
March 10, 2023
Year of graduation
2017 — 9 yrs since
Specialty taxonomy
363LA2100X — NUCC code
State licenses (3)
Missouri #2023006109 · Missouri #2018001739 · Illinois #277.000663

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1437667490. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
32
Distinct HCPCS
1
Medicare allowed
$4,594
HCPCS Description Services Patients Avg allowed
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 32 32 $144

In context: peer comparison

Among 1 peers in this city , average services per provider: 32. This provider delivers 1.0× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$20
Transactions
1
Manufacturers
1
Payer (manufacturer) Industry Txns Amount
ZOLL Services LLC (A/K/A ZOLL LifeCor Corp) 1 $20.11

By nature of payment

Food and Beverage
$20

Frequently asked questions

Auto-generated from federal data
What is Dr. Spencer Mares's medical specialty?
Dr. Spencer Mares practices Acute Care Nurse Practitioner in Lake Saint Louis, MO.
Where does Dr. Spencer Mares practice?
Dr. Spencer Mares practices at 100 Medical Plz, Lake Saint Louis, MO 633671366. Office phone: 6366255200.
What is Dr. Spencer Mares's NPI?
Dr. Spencer Mares's National Provider Identifier (NPI) is 1437667490, issued by NPPES.
Does Dr. Spencer Mares accept Medicare assignment?
Yes. Dr. Spencer Mares accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Spencer Mares commonly perform?
Top Medicare-reported procedures in 2023: Initial hospital care with moderate level of medical decision making (HCPCS 99223). Source: CMS Medicare Physician & Other Practitioners file.