Quick answers
- Which hospitals does Mark Sullivan work at?
- Medicare's official clinician data lists Mark Sullivan at 1 hospital: Portsmouth Regional Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Mark Sullivan see patients?
- Medicare's clinician data lists 2 practice locations, including Portsmouth, NH. Call before your visit to confirm the address.
- What is Mark Sullivan's specialty?
- Medicare lists Physician Assistant as the primary specialty.
- Does Mark Sullivan accept Medicare assignment?
- Yes. Medicare's clinician data says Mark Sullivan accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for Mark Sullivan?
- (603) 431-5242, as listed in official Medicare / NPI Registry data.
- What is Mark Sullivan's NPI number?
- 1225075328. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Mark Sullivan works
Medicare's Facility Affiliation Data lists Mark Sullivan at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Portsmouth Regional HospitalPortsmouth, NH · Acute Care Hospital · CCN 300029
Practice locations
Addresses where Mark Sullivan is enrolled with Medicare (CMS data updated 2026-10-02).
- 330 Borthwick Ave, Suite 308Portsmouth, NH 03801 (603) 431‑5242
- 333 Borthwick AvePortsmouth, NH 03801
Group practices
Medicare enrollment lists Mark Sullivan as a member of this group (CMS data updated 2026-10-02).
- Appledore Medical Group Inc196 clinicians in the group
Specialties
- Physician Assistantprimary
Other physician assistants in Portsmouth
Clinicians with the same Medicare primary specialty in Portsmouth, NH — not a recommendation.
Clinician information
| Credential | PA |
|---|---|
| Graduation year | 1992 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1225075328 |
| 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 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- 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