DR. MARA HARMELIN HORWITZ MD
NPI 1649613332
Internal Medicine - Rheumatology in Saint Louis, MO

Active since April 11, 2013PECOS EnrolledAccepts Medicare Assignment
1225 S GRAND BLVD, SAINT LOUIS, MO 63104(314) 977-8833 Get Directions Write a Review

NPPES record last updated: February 5, 2021. Verified against the NPPES registry weekly; last sync: July 26, 2026.

About Dr. Mara Harmelin Horwitz Md NPPES

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

DR. MARA HARMELIN HORWITZ MD (NPI 1649613332) is an individual rheumatology provider in Saint Louis, Missouri, licensed in Missouri (2016009340) and active in the NPI registry since April 2013. She is enrolled in Medicare PECOS, is affiliated with Tacoma General Allenmore Hospital, and is a graduate of Southern Illinois University School Of Medicine (2013).

NPPES Registry Identity

NPI1649613332
Entity TypeIndividualFemale
Primary Taxonomy207RR0500X
Provider Legal NameDR. MARA HARMELIN HORWITZCredential: MD
Location Address1225 S GRAND BLVDSaint Louis, MO 63104-1016
Mailing Address1402 S Grand Blvd Rm R213aSaint Louis, MO 63104-1004 · (314) 977-8833
Sole ProprietorNo
Medical School CMSSouthern Illinois University School Of MedicineGraduated 2013
Enumeration DateApril 11, 2013
Last NPPES UpdateFebruary 5, 2021
NPPES CertifiedFebruary 5, 2021
NPI 1649613332 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 3

Primary SpecialtyInternal Medicine · RheumatologyAllopathic & Osteopathic Physicians
Taxonomy Code207RR0500X
License Licensed in MO · 2016009340
Definition

An internist who treats diseases of joints, muscle, bones and tendons. This specialist diagnoses and treats arthritis, back pain, muscle strains, common athletic injuries and collagen diseases.

Also ListedPediatrics · Pediatric RheumatologyTaxonomy 2080P0216X · License 2016009340 (MO)
1225 S GRAND BLVD, Saint Louis, MO 63104

Accepted 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

Dr. Mara Harmelin Horwitz Md 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 ID2961793328
PECOS Enrollment IDI20221028002506
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

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.

Established patient office or other outpatient visit, 30-39 minutes 99214
This is a routine check-up for patients who have previously visited our clinic. It involves a comprehensive review of your health and any ongoing treatments. The consultation lasts between 30-39 minutes, allowing enough time to discuss any concerns.
81 services64 patients

Hospital Affiliations CMS Care Compare

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

Tacoma General Allenmore Hospital

Acute Care Hospitals · Tacoma, WA
2/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number500129
Location315 S Mlk Jr WayTacoma, WA 98405 · Pierce County
Emergency services Birthing friendly

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.

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.

Psychiatry & Neurology (Vascular Neurology)
1225 S GRAND BLVD
SAINT LOUIS, MO 63104
Nurse Practitioner (Adult Health)
1225 S GRAND BLVD
SAINT LOUIS, MO 63104
Psychiatry & Neurology (Neurology)
1225 S GRAND BLVD
SAINT LOUIS, MO 63104
Optometrist (Low Vision Rehabilitation)
1225 S GRAND BLVD
SAINT LOUIS, MO 63104
Ophthalmology
1225 S GRAND BLVD
SAINT LOUIS, MO 63104
Ophthalmology
1225 S GRAND BLVD
SAINT LOUIS, MO 63104
Ophthalmology
1225 S GRAND BLVD
SAINT LOUIS, MO 63104
Ophthalmology
1225 S GRAND BLVD
SAINT LOUIS, MO 63104

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 Mara Horwitz's NPI number?

The NPI number for Mara Horwitz is 1649613332. It was assigned to this individual provider in the NPPES registry on April 11, 2013.

Where is Mara Horwitz located?

Mara Horwitz practices at 1225 S Grand Blvd, Saint Louis, MO 63104. The listed phone number is (314) 977-8833.

What is Mara Horwitz's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Rheumatology, with taxonomy code 207RR0500X.

Is Mara Horwitz enrolled in Medicare?

Yes. Mara Horwitz 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 Mara Horwitz accept?

Health plans from Premera Blue Cross Blue Shield of Alaska and Providence Health Plan list Mara Horwitz 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 Mara Horwitz affiliated with any hospitals?

According to CMS data, Mara Horwitz is affiliated with Tacoma General Allenmore Hospital.

When was this NPI record last updated?

The NPPES record for Mara Horwitz was last updated on February 5, 2021. NPI Profile syncs with the weekly NPPES data releases published by CMS.