Karen Ahlert, M.D.
NPI 1083819502 · Surgery Physician · Cambridge, MA
Enrolled with Medicare as Practitioner - General Surgery · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Karen Ahlert, M.D. is a Surgery Physician provider in Cambridge, MA (NPI 1083819502).
Provider details
- NPI number
- 1083819502
- Entity type
- Individual
- Primary specialty
- Surgery PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Female
- Sole proprietor
- No
- License
- L-231744 (MA)
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
19 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
85 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) |
|---|---|---|
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 24 | $181 |
| New Patient Office Or Other Outpatient Visit With Low Level of Medical Decision Making, If Using Time, 30 Minutes Or More99203 | 18 | $122 |
| Diagnostic Exam of Anus Using an Endoscope46600 | 16 | $131 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 16 | $196 |
| New Patient Office Or Other Outpatient Visit With a High Level of Medical Decision Making, If Using Time, 60 Minutes Or More99205 | 11 | $237 |
Typical Medicare-allowed amounts for these services range $122–$237 (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.
Practice location
Mailing address
Registry dates
- Enumerated
- 2007-06-15
- Last updated
- 2017-03-20
Frequently asked questions
- What is Karen Ahlert's NPI number?
- Karen Ahlert's National Provider Identifier (NPI) is 1083819502, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Karen Ahlert's specialty?
- Karen Ahlert is listed in the NPPES registry with a primary specialty of Surgery Physician (Allopathic & Osteopathic Physicians).
- Where is Karen Ahlert located?
- Karen Ahlert's practice location on file with NPPES is 300 Mount Auburn St, Cambridge, MA 02138-5600.
- What is Karen Ahlert's phone number?
- The practice phone number listed in the NPPES registry for Karen Ahlert is (617) 868-7456.
- Does Karen Ahlert accept Medicare?
- Karen Ahlert is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Karen Ahlert's NPI active?
- Yes — Karen Ahlert's NPI (1083819502) is active in the NPPES registry as of the last update on 2017-03-20.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.