Christianna Sim, MD
NPI 1396235743 · Emergency Medicine Physician · Santa Monica, CA
Enrolled with Medicare as Practitioner - Emergency Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Christianna Sim, MD is a Emergency Medicine Physician provider in Santa Monica, CA (NPI 1396235743).
Provider details
- NPI number
- 1396235743
- Entity type
- Individual
- Primary specialty
- Emergency Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- A185926 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
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
3 documented practice locations
- Medicare service volume (vs. specialty peers)28% of score
366 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 High Level of Medical Decision Making99285 | 247 | $186 |
| Emergency Department Visit With Moderate Level of Medical Decision Making99284 | 39 | $128 |
| Critical Care, First 30-74 Minutes99291 | 36 | $233 |
| Ultrasound of Heart, Follow-Up93308 | 27 | $28 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 17 | $194 |
Typical Medicare-allowed amounts for these services range $28–$233 (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
Additional practice locations (2)
- 300 Pasteur DrStanford, CA 94305-2200Phone: (650) 723-4000
- 450 Clarkson AveBrooklyn, NY 11203-2012Phone: (718) 270-6315
Registry dates
- Enumerated
- 2018-05-11
- Last updated
- 2025-08-29
- Certified
- 2025-08-29
Frequently asked questions
- What is Christianna Sim's NPI number?
- Christianna Sim's National Provider Identifier (NPI) is 1396235743, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Christianna Sim's specialty?
- Christianna Sim is listed in the NPPES registry with a primary specialty of Emergency Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Christianna Sim located?
- Christianna Sim's practice location on file with NPPES is 1250 16th St, Santa Monica, CA 90404-1249.
- What is Christianna Sim's phone number?
- The practice phone number listed in the NPPES registry for Christianna Sim is (310) 794-0585.
- Does Christianna Sim accept Medicare?
- Christianna Sim is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Christianna Sim's NPI active?
- Yes — Christianna Sim's NPI (1396235743) is active in the NPPES registry as of the last update on 2025-08-29.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.