Catharina Armstrong, MD
NPI 1538295217 · Internal Medicine Physician · Worcester, MA
Enrolled with Medicare as Practitioner - Infectious Disease · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Catharina Armstrong, MD is a Internal Medicine Physician provider in Worcester, MA (NPI 1538295217).
Provider details
- NPI number
- 1538295217
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- L-221067 (MA)
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
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
4 documented practice locations
- Medicare service volume (vs. specialty peers)28% of score
25 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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 25 | $102 |
Typical Medicare-allowed amounts for these services range $102–$102 (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.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 2 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Buprenorphine Hcl/Naloxone Hclbrand: Buprenorphine-Naloxone | 57 | 15 |
| Naltrexone Hcl | 21 | — |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Practice location
Mailing address
Additional practice locations (3)
- Massachusetts General Hospital55 Fruit StreetBoston, MA 02114Phone: (617) 726-2066
- 157 Union StMarlborough, MA 01752-1228Phone: (508) 486-5678Fax: (508) 486-5677
- 55 Lake Ave NWorcester, MA 01655-0002Phone: (508) 334-8515Fax: (508) 334-6490
Registry dates
- Enumerated
- 2007-02-26
- Last updated
- 2021-03-25
- Certified
- 2021-03-25
Frequently asked questions
- What is Catharina Armstrong's NPI number?
- Catharina Armstrong's National Provider Identifier (NPI) is 1538295217, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Catharina Armstrong's specialty?
- Catharina Armstrong is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Catharina Armstrong located?
- Catharina Armstrong's practice location on file with NPPES is 119 Belmont St, Worcester, MA 01605-2903.
- What is Catharina Armstrong's phone number?
- The practice phone number listed in the NPPES registry for Catharina Armstrong is (508) 334-8515.
- Does Catharina Armstrong accept Medicare?
- Catharina Armstrong is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Catharina Armstrong's NPI active?
- Yes — Catharina Armstrong's NPI (1538295217) is active in the NPPES registry as of the last update on 2021-03-25.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.