Colleen Grassley, PA-C
NPI 1659887073 · Physician Assistant · Ann Arbor, MI
Enrolled with Medicare as Practitioner - Physician Assistant · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Colleen Grassley, PA-C is a Physician Assistant provider in Ann Arbor, MI (NPI 1659887073).
Provider details
- NPI number
- 1659887073
- Entity type
- Individual
- Primary specialty
- Physician AssistantPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- PA-C
- Sex
- Female
- Sole proprietor
- No
- License
- 5601010555 (MI)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
8 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
11 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Emergency Department Visit With Moderate Level of Medical Decision Making99284 | 11 | $106 |
Typical Medicare-allowed amounts for these services range $106–$106 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
Practice location
Mailing address
Registry dates
- Enumerated
- 2017-12-21
- Last updated
- 2021-08-18
- Certified
- 2021-08-18
Frequently asked questions
- What is Colleen Grassley's NPI number?
- Colleen Grassley's National Provider Identifier (NPI) is 1659887073, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Colleen Grassley's specialty?
- Colleen Grassley is listed in the NPPES registry with a primary specialty of Physician Assistant (Physician Assistants & Advanced Practice Nursing Providers).
- Where is Colleen Grassley located?
- Colleen Grassley's practice location on file with NPPES is 1500 E Medical Center Dr, Ann Arbor, MI 48109-5000.
- What is Colleen Grassley's phone number?
- The practice phone number listed in the NPPES registry for Colleen Grassley is (734) 936-4000.
- Does Colleen Grassley accept Medicare?
- Colleen Grassley is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Colleen Grassley's NPI active?
- Yes — Colleen Grassley's NPI (1659887073) is active in the NPPES registry as of the last update on 2021-08-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.