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DR. MICHELLE GRENNAN PH.D.
NPI 1922544477
Psychologist - Clinical in Mount Vernon, NY

Active since January 09, 2017PECOS Enrolled
765 GRAMATAN AVE, MOUNT VERNON, NY 10552(914) 310-7943 Get Directions Write a Review

NPPES record last updated: September 17, 2019. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Sep 17, 2019, Jan 9, 2017 (2 updates tracked since 2017).

About Dr. Michelle Grennan Ph.d. NPPES

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

DR. MICHELLE GRENNAN PH.D. (NPI 1922544477) is an individual clinical provider in Mount Vernon, New York, licensed in New York (021973) and active in the NPI registry since January 2017. She is enrolled in Medicare PECOS and is a graduate of Other (2015).

NPPES Registry Identity

NPI1922544477
Entity TypeIndividualFemale
Primary Taxonomy103TC0700X
Provider Legal NameDR. MICHELLE GRENNANCredential: PH.D.
Location Address765 GRAMATAN AVEMount Vernon, NY 10552-1043
Mailing Address765 Gramatan AveMount Vernon, NY 10552-1043 · (914) 310-7943
Phone(914) 310-7943
Sole ProprietorYes
Medical School CMSOtherGraduated 2015
Enumeration DateJanuary 9, 2017
Last NPPES UpdateSeptember 17, 20192 updates tracked since enumeration
✔ NPI 1922544477 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyPsychologist · ClinicalBehavioral Health & Social Service Providers
Taxonomy Code103TC0700X
License✔ Licensed in NY · 021973
Definition
A psychologist who provides continuing and comprehensive mental and behavioral health care for individuals and families; consultation to agencies and communities; training, education and supervision; and research-based practice. It is a specialty in breadth -- one that is broadly inclusive of severe psychopathology -- and marked by comprehensiveness and integration of knowledge and skill from a broad array of disciplines within and outside of psychology proper. The scope of clinical psychology encompasses all ages, multiple diversities and varied systems.
765 GRAMATAN AVE, Mount Vernon, NY 10552
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Medicare Participation & PECOS CMS

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

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Dr. Michelle Grennan Ph.d. is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

PECOS PAC ID9931482841
PECOS Enrollment IDI20170220000086
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 Michelle Grennan reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Epilepsy Foundation Of L.I.
18 mi
Voluntary or Charitable
506 STEWART AVE
Garden City, NY 11530
  • Reassigned Medicare billing, New York enrollment
  • Medicare enrollment name: Epic Long Island
  • 110 clinicians in this Medicare group
NPI 1467755785 (516) 739-7733

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

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.

Psychotherapy, 45 minutes 90834
Psychotherapy is a treatment method where you converse with a therapist about your thoughts, feelings, and behaviors. In a 45-minute session, the therapist assists you in understanding and managing your mental health concerns, improving emotional wellness, and promoting personal growth.
318 services11 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 10552 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
$203.53 typical visit price
range $67.40 – $203.53
Typical copayment $50.88 (range $16.85 – $50.88)
Most-billed visit code 99205
Established Patient
$117.62 typical visit price
range $21.66 – $164.45
Typical copayment $29.40 (range $5.41 – $41.11)
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 2

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

LEWIS A. OPLER, M.D., PH.D., P.C.
Psychiatry & Neurology (Psychiatry)
765 GRAMATAN AVE
MOUNT VERNON, NY 10552
Westchester County (914) 668-4799
PAUL GRENNAN
Counselor (Mental Health)
765 GRAMATAN AVE
MOUNT VERNON, NY 10552
Westchester County (914) 320-3963

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 Michelle Grennan's NPI number?

The NPI number for Michelle Grennan is 1922544477. It was assigned to this individual provider in the NPPES registry on January 9, 2017.

Where is Michelle Grennan located?

Michelle Grennan practices at 765 Gramatan Ave, Mount Vernon, NY 10552. The listed phone number is (914) 310-7943.

What is Michelle Grennan's specialty?

The primary specialty registered for this NPI is Psychologist, specializing in Clinical, with taxonomy code 103TC0700X.

Is Michelle Grennan enrolled in Medicare?

Yes. Michelle Grennan is registered in the Medicare PECOS enrollment system.

Which organization bills Medicare for Michelle Grennan's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Michelle Grennan reassigns Medicare benefits to Epilepsy Foundation Of L.I. (Garden City, NY). 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 Michelle Grennan'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 Michelle Grennan was last updated on September 17, 2019. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 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.