SPENCER JOHN MARES FNP-C, AGACNP-BC
NPI 1437667490
Nurse Practitioner - Acute Care in Lake Saint Louis, MO

Q: What is Spencer Mares's NPI number?

The NPI number for Spencer Mares is 1437667490. It was assigned to this individual provider in the NPPES registry on January 11, 2018.

Q: What is Spencer Mares's specialty?

The primary specialty registered for this NPI is Nurse Practitioner, specializing in Acute Care, with taxonomy code 363LA2100X.

Q: When was this NPI record last updated?

The NPPES record for Spencer Mares was last updated on March 10, 2023. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 3 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.

Active since January 11, 2018PECOS EnrolledAccepts Medicare Assignment

100 MEDICAL PLZ, LAKE SAINT LOUIS, MO 63367(636) 625-5200 Get Directions Write a Review

NPPES record last updated: March 10, 2023. Verified against the NPPES registry weekly; last sync: August 16, 2026.

Record update history: Mar 10, 2023, Mar 5, 2019, Mar 29, 2018 and 2 more (5 updates tracked since 2018).

On this page

About Spencer John Mares Fnp-c, Agacnp-bc NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

SPENCER JOHN MARES FNP-C, AGACNP-BC (NPI 1437667490) is an individual acute care provider in Lake Saint Louis, Missouri, licensed in Missouri (2023006109) and active in the NPI registry since January 2018. He is enrolled in Medicare PECOS, is affiliated with Ssm St Joseph Health Center, and is a graduate of Other (2017).

NPPES Registry Identity

NPI1437667490

Entity TypeIndividualMale

Primary Taxonomy363LA2100X

Provider Legal NameSPENCER JOHN MARESCredential: FNP-C, AGACNP-BC

Location Address100 MEDICAL PLZLake Saint Louis, MO 63367-1366

Mailing Address50 Meadow Run CtSaint Peters, MO 63303-5805 · (636) 485-3683

Phone(636) 625-5200

Sole ProprietorNo

Medical School CMSOtherGraduated 2017

Enumeration DateJanuary 11, 2018

Last NPPES UpdateMarch 10, 20235 updates tracked since enumeration

NPPES CertifiedMarch 10, 2023

✔ NPI 1437667490 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyNurse Practitioner · Acute CarePhysician Assistants & Advanced Practice Nursing Providers

Taxonomy Code363LA2100X

License✔ Licensed in MO · 2023006109

Also ListedNurse Practitioner · FamilyTaxonomy 363LF0000X · License 2018001739 (MO), 277.000663 (IL)

100 MEDICAL PLZ, Lake Saint Louis, MO 63367

Open in Google Maps ↗

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Anthem Blue Cross and Blue Shield, Oscar Insurance Company.Insurance ›

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, and ordering and referring status from the CMS PECOS system.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Spencer John Mares Fnp-c, Agacnp-bc is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID3072872811

PECOS Enrollment IDI20180124000475

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Areas of Expertise CMS Part B claims 4

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 99223

Initial hospital inpatient care per day, typically 70 minutes, refers to the daily medical service provided to patients admitted to the hospital. This includes a comprehensive evaluation, diagnosis, treatment plan, and monitoring of your health condition. It ensures your well-being during your hospital stay.

194 services181 patients

Advance care planning, first 30 minutes 99497

Advance care planning is a process where you discuss your healthcare preferences with your doctor. This conversation, lasting up to 30 minutes, helps ensure your wishes are respected if you're unable to communicate them in the future. It's about your care, your way.

72 services70 patients

Critical care, first 30-74 minutes 99291

Critical care involves immediate and constant attention by a team of specially-trained health professionals. It's for patients with life-threatening conditions, requiring first 30-74 minutes of intense monitoring and treatment.

63 services58 patients

Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes 99222

Initial hospital inpatient care is a service where a healthcare provider spends about 50 minutes per day overseeing your care while you're admitted in the hospital. This includes reviewing your health status, planning your treatment, and ensuring your safety and comfort.

30 services30 patients

Hospital Affiliations CMS Care Compare 2

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

Ssm St Joseph Health Center

Acute Care Hospitals · Saint Charles, MO

3/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number260005

Location300 1st Capitol DrSaint Charles, MO 63301 · St. Charles County

Emergency services

Ssm St Joseph Hospital West

Acute Care Hospitals · Lake Saint Louis, MO

3/5 CMS rating

OwnershipVoluntary non-profit - Church

CMS Certification Number260200

Location100 Medical PlazaLake Saint Louis, MO 63367 · St. Charles County

Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 63367 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient

$86.32 typical visit price

range $55.65 – $169.38

Typical copayment $21.58 (range $13.91 – $42.34)

Most-billed visit code 99203

Established Patient

$98.37 typical visit price

range $17.76 – $137.92

Typical copayment $24.59 (range $4.44 – $34.48)

Most-billed visit code 99214

Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

VICTORIA LYNN HINES NP

Nurse Practitioner

100 MEDICAL PLZ
LAKE ST LOUIS, MO 63367

St. Charles County (636) 625-5200

LAKE FOREST EMERGENCY GROUP LLC

Emergency Medicine

100 MEDICAL PLZ
LAKE ST LOUIS, MO 63367

St. Charles County (636) 625-5200

EVE WEINDELL BARNOSKI LPTA

Physical Therapy Assistant

100 MEDICAL PLZ
LAKE SAINT LOUIS, MO 63367

St. Charles County (636) 485-7608

JOSHUA HARKLESS MD

Emergency Medicine

100 MEDICAL PLZ
LAKE ST LOUIS, MO 63367

St. Charles County (636) 625-5300

MELISSA COLLEEN HYNES MHS, CCC-SLP

Speech-Language Pathologist

100 MEDICAL PLZ
LAKE ST LOUIS, MO 63367

St. Charles County (636) 755-3997

AKIKO OKABE AGACNP

Nurse Practitioner (Acute Care)

100 MEDICAL PLZ
LAKE ST LOUIS, MO 63367

St. Charles County (314) 317-0600

KENDRICK J WILLIAMS MD

Pediatrics

100 MEDICAL PLZ
LAKE SAINT LOUIS, MO 63367

St. Charles County (636) 625-5300

YUNHEE CHOI CRUSE CNP, FNP-BC

Nurse Practitioner (Family)

100 MEDICAL PLZ
LAKE ST LOUIS, MO 63367

St. Charles County (636) 625-5200

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Spencer Mares's NPI number?

The NPI number for Spencer Mares is 1437667490. It was assigned to this individual provider in the NPPES registry on January 11, 2018.

Where is Spencer Mares located?

Spencer Mares practices at 100 Medical Plz, Lake Saint Louis, MO 63367. The listed phone number is (636) 625-5200.

What is Spencer Mares's specialty?

The primary specialty registered for this NPI is Nurse Practitioner, specializing in Acute Care, with taxonomy code 363LA2100X.

Is Spencer Mares enrolled in Medicare?

Yes. Spencer Mares is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

What insurance does Spencer Mares accept?

Health plans from Anthem Blue Cross and Blue Shield and Oscar Insurance Company list Spencer Mares as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

Is Spencer Mares affiliated with any hospitals?

According to CMS data, Spencer Mares is affiliated with Ssm St Joseph Health Center and Ssm St Joseph Hospital West.

When was this NPI record last updated?

The NPPES record for Spencer Mares was last updated on March 10, 2023. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 3 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.