Spencer John Mares, FNP-C, AGACNP-BC
Acute Care Nurse Practitioner · Lake Saint Louis, MO
Spencer John Mares, FNP-C, AGACNP-BC is an acute care nurse practitioner with a practice address in Lake Saint Louis, Missouri, and NPI 1437667490, issued on Jan 11, 2018. Check the license (Missouri 2023006109, as entered in NPPES) with the Missouri board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Spencer John Mares
- Credential
- FNP-C, AGACNP-BC
- Primary taxonomy
- Acute Care Nurse Practitioner 363LA2100X
- License numbers
- 2023006109 MO
2018001739 MO
277.000663 IL
Self-reported in NPPES; status is on the state search - Practice location
- 100 Medical Plz, Lake Saint Louis, MO 63367
- Phone
- (636) 625-5200
- Enumerated
- Jan 11, 2018
- Record last updated
- Mar 10, 2023
- Medicare enrollment
- Enrolled (PECOS I20180124000475); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest acute care nurse practitioner records → All 441 in Missouri → Look up another NPI →
Also registered at 100 Medical Plz
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Ross Belew, PHARMDPharmacist1205587227
- Alison Chaney, R.D., L.D.Registered Dietitian1780959288
- Kenneth Choinka, OTOccupational Therapist1255160628
- Numan Choudhry, M.D.Family Medicine Physician1528591633
- Christopher Coriasso, DOCritical Care Medicine (Internal Medicine) Physician1194255455
Verify Spencer John Mares in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich Missouri board licenses this profession
Search for license 2023006109Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Industry payments in 2024: $20.11
1 payment: food and beverage; the largest payer was Zoll Services LLC (a/k/a Zoll LifeCor Corp). The 10,984 providers of this specialty with any payment received $647.94 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through 2 group practices
- Sound Physicians OF Illinois LLCLake Saint Louis, MO
- Ssm Medical Group IncSaint Charles, MO
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Spencer John Mares among 441 acute care nurse practitioner records in Missouri
Spencer John Mares, FNP-C, AGACNP-BC is one of 441 acute care nurse practitioner records with a practice address in Missouri. 80% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2018, is newer than 42% of them.
- NPI issued2018 · 42% of these records are older, 53% newer
- In a Medicare fileYes · 80% of these records are
- In the CMS Doctors and Clinicians fileYes · 73% of these records are
- Graduated2017 · median 2019 among the 324 with a school on file
- Record last updated2023 · 34% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363LA2100X and a Missouri practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Acute Care Nurse Practitioner providers in Missouri
There are 441 acute care nurse practitioner records in Missouri.
All 441 in Missouri → Every provider in Lake Saint Louis → Acute Care Nurse Practitioner nationwide →
The 8 acute care nurse practitioner records with the nearest ZIP codes
- Akiko Okabe, AGACNPLake St Louis, MO 633671073910162
- Heather UelhofO Fallon, MO 633681881296788
- Corey Blassie, NPSaint Peters, MO 633761134755911
- Emily Bock, AGACNP-BCHannibal, MO 634011922932102
- Lauren Brandenburger, ACNP-BCHannibal, MO 634011942668819
- Alyssa Crowe, ACNPHannibal, MO 634011336645035
- Amanda Curry, NPHannibal, MO 634011154918332
- Lynn Shima, APNHannibal, MO 634011063489441
Common questions
What is Spencer John Mares, FNP-C, AGACNP-BC's NPI number?
Spencer John Mares, FNP-C, AGACNP-BC's National Provider Identifier (NPI) is 1437667490, issued on Jan 11, 2018. An NPI identifies a provider in billing; it is not a license.
Where is Spencer John Mares, FNP-C, AGACNP-BC located?
The NPPES record lists a practice address at 100 Medical Plz, Lake Saint Louis, MO, 63367. Phone: (636) 625-5200. Providers update this record themselves, so call before visiting.
How can I verify Spencer John Mares, FNP-C, AGACNP-BC's license?
NPPES lists Missouri license number 2023006109, as entered by the provider. Search the Missouri board that licenses this profession; the NPPES record confirms identity only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.