1. Home
  2. Directory
  3. Missouri
  4. Saint Louis
  5. Internal Medicine
  6. NPI Profile
Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

GERALD MAHON M.D.
NPI 1154302289
Internal Medicine - Geriatric Medicine in Saint Louis, MO

Active since November 07, 2005PECOS Enrolled
1201 S GRAND BLVD, SAINT LOUIS, MO 63104(314) 977-8462(314) 977-3370 Get Directions Write a Review

NPPES record last updated: November 8, 2026. Verified against the NPPES registry weekly; last sync: November 08, 2026.

Record update history: Nov 8, 2026, Mar 12, 2021 (2 updates tracked since 2021).

About Gerald Mahon M.d. NPPES

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

GERALD MAHON M.D. (NPI 1154302289) is an individual geriatric medicine provider in Saint Louis, Missouri, licensed in Missouri (R4H74) and active in the NPI registry since November 2005. He is enrolled in Medicare PECOS.

NPPES Registry Identity

NPI1154302289
Entity TypeIndividualMale
Primary Taxonomy207RG0300X
Provider Legal NameGERALD MAHONCredential: M.D.
Location Address1201 S GRAND BLVDSaint Louis, MO 63104-1016
Mailing Address1008 S Spring Ave Fl 2Saint Louis, MO 63110-2520 · (314) 977-8462 · Fax (314) 977-3370
Phone(314) 977-8462
Fax(314) 977-3370
Sole ProprietorNo
Enumeration DateNovember 7, 2005
Last NPPES UpdateNovember 8, 20262 updates tracked since enumeration
NPPES CertifiedMarch 12, 2021
✔ NPI 1154302289 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal Medicine · Geriatric MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207RG0300X
License✔ Licensed in MO · R4H74
Definition
An internist who has special knowledge of the aging process and special skills in the diagnostic, therapeutic, preventive and rehabilitative aspects of illness in the elderly. This specialist cares for geriatric patients in the patient's home, the office, long-term care settings such as nursing homes and the hospital.
1201 S GRAND BLVD, Saint Louis, MO 63104
Open in Google Maps ↗

Medicare Participation & PECOS CMS

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

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Gerald Mahon M.d. is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

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 Gerald Mahon 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.

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
$169.38 typical visit price
range $55.65 – $169.38
Typical copayment $42.34 (range $13.91 – $42.34)
Most-billed visit code 99205
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.

Referred Medical Equipment & Supplies CMS DME claims 2

Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.

Oxygen concentrator, single delivery port, capable of delivering 85 percent or greater oxygen concentration at the prescribed flow rate E1390
DME-Oxygen and Supplies · category DC002N
2 suppliers18 claims19 services$80.92 avg. paid by Medicare
Pharmacy dispensing fee for inhalation drug(s); per 30 days Q0513
DME-Other DME · category DE000N
3 suppliers12 claims12 services$20.31 avg. paid by Medicare
Dollar amounts are the average Medicare paid the supplier per service. They are not the cost to the patient.

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 Gerald Mahon's NPI number?

The NPI number for Gerald Mahon is 1154302289. It was assigned to this individual provider in the NPPES registry on November 7, 2005.

Where is Gerald Mahon located?

Gerald Mahon practices at 1201 S Grand Blvd, Saint Louis, MO 63104. The listed phone number is (314) 977-8462.

What is Gerald Mahon's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Geriatric Medicine, with taxonomy code 207RG0300X.

Is Gerald Mahon enrolled in Medicare?

Yes. Gerald Mahon is registered in the Medicare PECOS enrollment system.

Which organization bills Medicare for Gerald Mahon's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Gerald Mahon 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 Gerald Mahon's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for Gerald Mahon was last updated on November 8, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 days 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.