Matthew Warren, MD
NPI 1124412275 · 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)
Matthew Warren, MD is a Critical Care Medicine (Internal Medicine) Physician provider in Riverside, CA (NPI 1124412275).
Provider details
- NPI number
- 1124412275
- Entity type
- Individual
- Primary specialty
- Critical Care Medicine (Internal Medicine) PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- A170797 (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
11 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
112 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 | 47 | $225 |
| Subsequent Nursing Facility Care With Straightforward Level of Medical Decision Making, Per Day, If Using Time, at Least 10 Minutes99307 | 45 | $45 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 50 Minutes99233 | 20 | $126 |
Typical Medicare-allowed amounts for these services range $45–$225 (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.
$62 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
- 2015-03-26
- Last updated
- 2022-03-23
- Certified
- 2022-03-23
Frequently asked questions
- What is Matthew Warren's NPI number?
- Matthew Warren's National Provider Identifier (NPI) is 1124412275, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Matthew Warren's specialty?
- Matthew Warren is listed in the NPPES registry with a primary specialty of Critical Care Medicine (Internal Medicine) Physician (Allopathic & Osteopathic Physicians).
- Where is Matthew Warren located?
- Matthew Warren's practice location on file with NPPES is 4234 Riverwalk Pkwy Ste 230, Riverside, CA 92505-3312.
- What is Matthew Warren's phone number?
- The practice phone number listed in the NPPES registry for Matthew Warren is (951) 781-3672.
- Does Matthew Warren accept Medicare?
- Matthew Warren is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Matthew Warren's NPI active?
- Yes — Matthew Warren's NPI (1124412275) is active in the NPPES registry as of the last update on 2022-03-23.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.