Catherine Nguyen-Loh, DO
NPI 1558828848 · Family Medicine Physician · Fountain Valley, CA
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Catherine Nguyen-Loh, DO is a Family Medicine Physician provider in Fountain Valley, CA (NPI 1558828848).
Provider details
- NPI number
- 1558828848
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- DO
- Sex
- Female
- Sole proprietor
- No
- License
- 20A20201 (CA)
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
7 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
250 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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 135 | $138 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 67 | $97 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 20 | $140 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 14 | $180 |
| Annual Wellness Visit; Includes a Personalized Prevention Plan of Service (pps), Initial VisitG0438 | 14 | $178 |
Typical Medicare-allowed amounts for these services range $97–$180 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, 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.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 43 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 177 | 67 |
| Losartan Potassium | 113 | 39 |
| Levothyroxine Sodium | 107 | 33 |
| Amlodipine Besylate | 75 | 26 |
| Alendronate Sodium | 50 | 16 |
| Pantoprazole Sodium | 42 | 16 |
| Metformin Hcl |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$29 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
- 2019-02-22
- Last updated
- 2024-03-05
- Certified
- 2024-03-05
Frequently asked questions
- What is Catherine Nguyen-Loh's NPI number?
- Catherine Nguyen-Loh's National Provider Identifier (NPI) is 1558828848, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Catherine Nguyen-Loh's specialty?
- Catherine Nguyen-Loh is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Catherine Nguyen-Loh located?
- Catherine Nguyen-Loh's practice location on file with NPPES is 8970 Warner Ave, Fountain Valley, CA 92708-3211.
- What is Catherine Nguyen-Loh's phone number?
- The practice phone number listed in the NPPES registry for Catherine Nguyen-Loh is (714) 477-8400.
- Does Catherine Nguyen-Loh accept Medicare?
- Catherine Nguyen-Loh is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Catherine Nguyen-Loh's NPI active?
- Yes — Catherine Nguyen-Loh's NPI (1558828848) is active in the NPPES registry as of the last update on 2024-03-05.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.