Quick answers
- Does Gillian M. Brennan accept Medicare assignment?
- Yes. Medicare's clinician data says Gillian M. Brennan accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does Gillian M. Brennan see?
- In 2024, CMS data shows 13 Original Medicare patients and 14 services for Gillian M. Brennan. This counts Original Medicare only and measures volume, not quality.
- What is Gillian M. Brennan's NPI number?
- 1639210750. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for Gillian M. Brennan, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 13 |
|---|---|
| Services billed to Medicare | 14 |
| Different services or procedures | 12 |
| Participating Medicare provider | Yes |
| Average age of these patients | 76 |
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- High blood pressure75%
Hospitals where Gillian M. Brennan works
Medicare's Facility Affiliation Data lists Gillian M. Brennan at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- Northwell Hospital Glen CoveGlen Cove, NY · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 330181
Practice locations
Addresses where Gillian M. Brennan is enrolled with Medicare (CMS data updated October 2, 2026). The first 5 of 10; the Medicare profile lists all.
- 101 Saint Andrews LnGlen Cove, NY 11542
- 101 Saint Andrews Ln, Suite 1Glen Cove, NY 11542 (516) 674‑1812
- 221 Jericho TpkeSyosset, NY 11791
- 221 Jericho Tpke, Suite 3Syosset, NY 11791 (516) 496‑6558
- 221 Jericho TurnpikeSyosset, NY 11791 (516) 496‑6500
Group practices
Medicare enrollment lists Gillian M. Brennan as a member of this group (CMS data updated October 2, 2026).
- North Shore-Lij Medical PC6,440 clinicians in the group
Specialties
- Physician Assistantprimary
Other physician assistants in Glen Cove
Clinicians with the same Medicare primary specialty in Glen Cove, NY — not a recommendation.
Other clinicians in North Shore-Lij Medical PC
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | PA |
|---|---|
| Graduation year | 2003 |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1639210750 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians