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DR. JOSHUA CASEY MAYER D.O.
NPI 1679837322
Internal Medicine in Saint Louis, MO

Active since June 27, 2012PECOS EnrolledAccepts Medicare Assignment
81.57/100
CMS Quality Rating
1201 S GRAND BLVD, SAINT LOUIS, MO 63104(314) 257-8000(314) 577-8019 Get Directions Write a Review

NPPES record last updated: February 12, 2021. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Feb 12, 2021, Nov 30, 2020 (2 updates tracked since 2020).

About Dr. Joshua Casey Mayer D.o. NPPES

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

DR. JOSHUA CASEY MAYER D.O. (NPI 1679837322) is an individual internal medicine provider in Saint Louis, Missouri, licensed in Missouri (2018014496) and active in the NPI registry since June 2012. He is enrolled in Medicare PECOS, is affiliated with Ssm Health Saint Louis University Hospital, and is a graduate of Kansas City University Of Physicians And Surgeons (2012).

NPPES Registry Identity

NPI1679837322
Entity TypeIndividualMale
Primary Taxonomy207R00000X
Provider Legal NameDR. JOSHUA CASEY MAYERCredential: D.O.
Location Address1201 S GRAND BLVDSaint Louis, MO 63104-1016
Mailing Address1008 South Spring, Saint Louis University Academic PavilionSaint Louis, MO 63110-2520 · (314) 257-8222 · Fax (314) 577-8019
Phone(314) 257-8000
Fax(314) 577-8019
Sole ProprietorNo
Medical School CMSKansas City University Of Physicians And SurgeonsGraduated 2012
Enumeration DateJune 27, 2012
Last NPPES UpdateFebruary 12, 20212 updates tracked since enumeration
NPPES CertifiedJanuary 25, 2021
✔ NPI 1679837322 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
License✔ Licensed in MO · 2018014496
Definition
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
Also ListedHospitalistTaxonomy 208M00000X · License 2018014496 (MO)
1201 S GRAND BLVD, Saint Louis, MO 63104
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Accepted Insurance

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

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Joshua Casey Mayer D.o. 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 ID5597073312
PECOS Enrollment IDI20181129000143
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.

Medicare Billing Reassignment

Medicare enrollment records show Joshua Mayer reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Ssm Health Care Group
Same address
Internal Medicine
1225 SOUTH GRAND BLVD, 2L - DOOR 3,4
Saint Louis, MO 63104
  • Reassigned Medicare billing, Missouri enrollment
  • 1,294 clinicians in this Medicare group
NPI 1306589544 (314) 977-6100

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Areas of Expertise CMS Part B claims 6

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.

Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 99232
Follow-up hospital inpatient care involves daily check-ups while you're admitted in the hospital. Typically, a healthcare provider spends about 25 minutes each day reviewing your condition, adjusting treatment if needed, and answering any questions you might have.
97 services49 patients
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 99233
Follow-up hospital inpatient care per day typically involves a 35-minute check-up by your healthcare provider. This service includes monitoring your health progress, adjusting your treatment plan if needed, and answering any questions you may have about your condition or care.
68 services30 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.
21 services20 patients
Hospital discharge day management, 30 minutes or less 99238
Hospital discharge day management of 30 minutes or less includes finalizing your treatment, discussing your progress, and planning after-care at home. It ensures you're ready to leave the hospital and continue recovery safely.
19 services19 patients
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.
13 services12 patients
Hospital discharge day management, more than 30 minutes 99239
Hospital discharge day management over 30 minutes involves a detailed process to ensure a smooth transition from hospital to home. It includes final examinations, discussion of your hospital stay, post-discharge instructions, and coordinating follow-up care.
11 services11 patients

Hospital Affiliations CMS Care Compare

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

Ssm Health Saint Louis University Hospital

Acute Care Hospitals · Saint Louis, MO
1/5 CMS rating
OwnershipVoluntary non-profit - Church
CMS Certification Number260105
Location3635 Vista AveSaint Louis, MO 63110 · St. Louis City County
Emergency services

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 63104 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
$128.28 typical visit price
range $55.65 – $169.38
Typical copayment $32.07 (range $13.91 – $42.34)
Most-billed visit code 99204
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.

Medicare Quality Performance CMS QPP · MIPS

Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.

81.57/100
MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program
Scored as part of a group practice
Quality76.09
Promoting Interoperability100
Improvement Activities40
Cost54.28

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.

DOUG LONGO APRN
Nurse Practitioner (Acute Care)
1201 S GRAND BLVD
SAINT LOUIS, MO 63104
St. Louis City (314) 257-8000
JOHN JOSEPH HOUSER
Student in an Organized Health Care Education/Training Program
1201 S GRAND BLVD
SAINT LOUIS, MO 63104
St. Louis City (314) 257-8000
NABIHA NOOR SHAMSHUDDIN MD
Hospitalist
1201 S GRAND BLVD
SAINT LOUIS, MO 63104
St. Louis City (314) 257-8000
AMAN PATEL
Radiology (Diagnostic Radiology)
1201 S GRAND BLVD
SAINT LOUIS, MO 63104
St. Louis City (314) 257-8000
MS. KEELEY FERRELL RYAN PA-C
Physician Assistant
1201 S GRAND BLVD
SAINT LOUIS, MO 63104
St. Louis City (314) 257-1320
PATRICK SWEENEY
Student in an Organized Health Care Education/Training Program
1201 S GRAND BLVD
SAINT LOUIS, MO 63104
St. Louis City (314) 257-8000
DR. SHAMEELA NASRULLAH KHIMANI MD
Pediatrics
1201 S GRAND BLVD
SAINT LOUIS, MO 63104
St. Louis City (314) 617-3239
IBRAHIM SHAMASNEH M.D.
Hospitalist
1201 S GRAND BLVD
SAINT LOUIS, MO 63104
St. Louis City (314) 617-2000

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 Joshua Mayer's NPI number?

The NPI number for Joshua Mayer is 1679837322. It was assigned to this individual provider in the NPPES registry on June 27, 2012.

Where is Joshua Mayer located?

Joshua Mayer practices at 1201 S Grand Blvd, Saint Louis, MO 63104. The listed phone number is (314) 257-8000.

What is Joshua Mayer's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Joshua Mayer enrolled in Medicare?

Yes. Joshua Mayer 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.

Which organization bills Medicare for Joshua Mayer's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Joshua Mayer reassigns Medicare benefits to Ssm Health Care Group (Saint Louis, MO). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Joshua Mayer's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does Joshua Mayer accept?

Health plans from Anthem Blue Cross and Blue Shield list Joshua Mayer 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 Joshua Mayer affiliated with any hospitals?

According to CMS data, Joshua Mayer is affiliated with Ssm Health Saint Louis University Hospital.

When was this NPI record last updated?

The NPPES record for Joshua Mayer was last updated on February 12, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 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.