Quick answers
- Does Corissa A. McKallagat accept Medicare assignment?
- Yes. Medicare's clinician data says Corissa A. McKallagat 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 Corissa A. McKallagat see?
- In 2024, CMS data shows 205 Original Medicare patients and 278 services for Corissa A. McKallagat. This counts Original Medicare only and measures volume, not quality.
- What is Corissa A. McKallagat's NPI number?
- 1215249651. 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 Corissa A. McKallagat, 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 | 205 |
|---|---|
| Services billed to Medicare | 278 |
| Different services or procedures | 6 |
| Participating Medicare provider | Yes |
| Average age of these patients | 73 |
Most frequent services
- Established patient complete exam of visual system (92014)203 services
- Photography of the retina (92250)49 services
- New patient complete exam of visual system (92004)13 services
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 cholesterol63%
- High blood pressure51%
- Arthritis29%
- Anxiety18%
- Osteoporosis15%
- Ischemic heart disease11%
Practice locations
Addresses where Corissa A. McKallagat is enrolled with Medicare (CMS data updated October 2, 2026).
- 38 Daniel StPortsmouth, NH 03801 (603) 436‑4509
Specialties
- Optometryprimary
Other optometrists in Portsmouth
Clinicians with the same Medicare primary specialty in Portsmouth, NH — not a recommendation.
Clinician information
| Credential | OD |
|---|---|
| Optometry school | New England College Of Optometry |
| Graduation year | 2010 (16 years since optometry school) |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1215249651 |
| 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
- 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