Katherine Diemer, MD
NPI 1396906749 · Family Medicine Physician · Freeport, IL
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Katherine Diemer, MD is a Family Medicine Physician provider in Freeport, IL (NPI 1396906749).
Provider details
- NPI number
- 1396906749
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- 57640 (WI)
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 tenure28% of score
18 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
498 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 | 231 | $94 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 159 | $64 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 91 | $124 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 17 | $140 |
Typical Medicare-allowed amounts for these services range $64–$140 (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 · 116 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 308 | 72 |
| Lisinopril | 300 | 80 |
| Amlodipine Besylate | 229 | 66 |
| Levothyroxine Sodium | 225 | 56 |
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 194 | 48 |
| Metformin Hcl | 186 | 51 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2008-06-18
- Last updated
- 2020-12-18
- Certified
- 2020-12-18
Frequently asked questions
- What is Katherine Diemer's NPI number?
- Katherine Diemer's National Provider Identifier (NPI) is 1396906749, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Katherine Diemer's specialty?
- Katherine Diemer is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Katherine Diemer located?
- Katherine Diemer's practice location on file with NPPES is 1301 Kiwanis Dr, Freeport, IL 61032-6907.
- What is Katherine Diemer's phone number?
- The practice phone number listed in the NPPES registry for Katherine Diemer is (815) 235-1406.
- Does Katherine Diemer accept Medicare?
- Katherine Diemer is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Katherine Diemer's NPI active?
- Yes — Katherine Diemer's NPI (1396906749) is active in the NPPES registry as of the last update on 2020-12-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.