Karl Terwilliger, MD
NPI 1669426060 · Anesthesiology Physician · Waterloo, IA
Enrolled with Medicare as Practitioner - Anesthesiology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Karl Terwilliger, MD is a Anesthesiology Physician provider in Waterloo, IA (NPI 1669426060).
Provider details
- NPI number
- 1669426060
- Entity type
- Individual
- Primary specialty
- Anesthesiology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 34416 (IA)
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
20 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
132 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) |
|---|---|---|
| Insertion of Artery Tube for Blood Sampling Or Infusion Through Skin36620 | 48 | $40 |
| Insertion of Non-Tunneled Central Venous Tube for Infusion (5 Years Or Older)36556 | 32 | $76 |
| Insertion of Probe in Esophagus for Heart Ultrasound93313 | 22 | $10 |
| Anesthesia for Heart Artery Bypass Grafting on Heart-Lung Machine00567 | 18 | $758 |
| Ultrasonic Guidance for Needle Placement76942 | 12 | $28 |
Typical Medicare-allowed amounts for these services range $10–$758 (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.
$13 across 1 record (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
- 2006-05-20
- Last updated
- 2007-09-12
Frequently asked questions
- What is Karl Terwilliger's NPI number?
- Karl Terwilliger's National Provider Identifier (NPI) is 1669426060, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Karl Terwilliger's specialty?
- Karl Terwilliger is listed in the NPPES registry with a primary specialty of Anesthesiology Physician (Allopathic & Osteopathic Physicians).
- Where is Karl Terwilliger located?
- Karl Terwilliger's practice location on file with NPPES is 1825 Logan Ave, Waterloo, IA 50703-1916.
- What is Karl Terwilliger's phone number?
- The practice phone number listed in the NPPES registry for Karl Terwilliger is (319) 235-3886.
- Does Karl Terwilliger accept Medicare?
- Karl Terwilliger is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Karl Terwilliger's NPI active?
- Yes — Karl Terwilliger's NPI (1669426060) is active in the NPPES registry as of the last update on 2007-09-12.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.