Sonja Knittel-Hliddal, MD
NPI 1356846109 · Critical Care Medicine (Internal Medicine) Physician · Riverside, CA
Enrolled with Medicare as Practitioner - Critical Care (intensivists) · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Sonja Knittel-Hliddal, MD is a Critical Care Medicine (Internal Medicine) Physician provider in Riverside, CA (NPI 1356846109).
Provider details
- NPI number
- 1356846109
- Entity type
- Individual
- Primary specialty
- Critical Care Medicine (Internal Medicine) PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- Yes
- License
- A184723 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
8 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
963 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) |
|---|---|---|
| Critical Care, First 30-74 Minutes99291 | 556 | $211 |
| Critical Care, Each Additional 30 Minutes99292 | 310 | $105 |
| Ultrasonic Guidance for Blood Vessel Access76937 | 29 | $14 |
| Insertion of Non-Tunneled Central Venous Tube for Infusion (5 Years Or Older)36556 | 19 | $83 |
| Manual Attempt to Restore Blood Circulation and Breathing92950 | 19 | $180 |
| Emergent Insertion of Breathing Tube Into Windpipe Using an Endoscope31500 | 15 | $138 |
| Insertion of Artery Tube for Blood Sampling Or Infusion Through Skin |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$22 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
- 2018-03-26
- Last updated
- 2023-09-26
- Certified
- 2023-09-26
Frequently asked questions
- What is Sonja Knittel-Hliddal's NPI number?
- Sonja Knittel-Hliddal's National Provider Identifier (NPI) is 1356846109, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Sonja Knittel-Hliddal's specialty?
- Sonja Knittel-Hliddal is listed in the NPPES registry with a primary specialty of Critical Care Medicine (Internal Medicine) Physician (Allopathic & Osteopathic Physicians).
- Where is Sonja Knittel-Hliddal located?
- Sonja Knittel-Hliddal's practice location on file with NPPES is 4234 Riverwalk Pkwy Ste 230, Riverside, CA 92505-3312.
- What is Sonja Knittel-Hliddal's phone number?
- The practice phone number listed in the NPPES registry for Sonja Knittel-Hliddal is (856) 641-8000.
- Does Sonja Knittel-Hliddal accept Medicare?
- Sonja Knittel-Hliddal is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Sonja Knittel-Hliddal's NPI active?
- Yes — Sonja Knittel-Hliddal's NPI (1356846109) is active in the NPPES registry as of the last update on 2023-09-26.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.