Christopher Sonnenday, M.D.
NPI 1639103740 · Surgery Physician · Ann Arbor, MI
Enrolled with Medicare as Practitioner - General Surgery · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Christopher Sonnenday, M.D. is a Surgery Physician provider in Ann Arbor, MI (NPI 1639103740).
Provider details
- NPI number
- 1639103740
- Entity type
- Individual
- Primary specialty
- Surgery PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 4301088731 (MI)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
98 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
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 .
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) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 52 | $79 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 19 | $97 |
| Initial Hospital Care With Straightforward Or Low-Level Medical Decision Making, If Using Time, at Least 55 Minutes99222 | 16 | $132 |
| Preparation of Donor Kidney for Transplantation50323 | 11 | $167 |
Typical Medicare-allowed amounts for these services range $79–$167 (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.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$2,757 across 3 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-07-11
- Last updated
- 2012-04-19
Frequently asked questions
- What is Christopher Sonnenday's NPI number?
- Christopher Sonnenday's National Provider Identifier (NPI) is 1639103740, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Christopher Sonnenday's specialty?
- Christopher Sonnenday is listed in the NPPES registry with a primary specialty of Surgery Physician (Allopathic & Osteopathic Physicians).
- Where is Christopher Sonnenday located?
- Christopher Sonnenday's practice location on file with NPPES is 1500 East Medical Center Dr, Ann Arbor, MI 48109-5332.
- What is Christopher Sonnenday's phone number?
- The practice phone number listed in the NPPES registry for Christopher Sonnenday is (734) 936-5738.
- Does Christopher Sonnenday accept Medicare?
- Christopher Sonnenday is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Christopher Sonnenday's NPI active?
- Yes — Christopher Sonnenday's NPI (1639103740) is active in the NPPES registry as of the last update on 2012-04-19.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.