Quick answers
- Does Karen J. Mass accept Medicare assignment?
- Yes. Medicare's clinician data says Karen J. Mass accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does Karen J. Mass see?
- In 2024, CMS data shows 358 Original Medicare patients and 1,676 services for Karen J. Mass. This counts Original Medicare only and measures volume, not quality.
- What is Karen J. Mass's NPI number?
- 1710179759. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for Karen J. Mass, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 358 |
|---|---|
| Services billed to Medicare | 1,676 |
| Different services or procedures | 61 |
| Participating Medicare provider | Yes |
| Average age of these patients | 73 |
Most frequent services
- Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)254 services
- Pelvic exam (99459)244 services
- Screening 3d breast mammography (77063)167 services
- Screening mammography (77067)167 services
- Annual depression screening, 5 to 15 minutes (G0444)106 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- High cholesterol70%
- Arthritis49%
- High blood pressure48%
- Osteoporosis32%
- Anxiety17%
- Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)16%
Hospitals where Karen J. Mass works
Medicare's Facility Affiliation Data lists Karen J. Mass at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- Northshore University Healthsystem - Evanston HospitalEvanston, IL · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 140010
- Northwestern Lake Forest HospitalLake Forest, IL · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 140130
- Northwestern Medicine Central Dupage HospitalWinfield, IL · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 140242
- Northwestern Memorial HospitalChicago, IL · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 140281
Practice locations
Addresses where Karen J. Mass is enrolled with Medicare (CMS data updated October 2, 2026).
- 1475 E Belvidere Rd, Suite 212Grayslake, IL 60030 (847) 295‑0433
Specialties
- Obstetrics/Gynecologyprimary
Other OB-GYNs in Illinois
Clinicians with the same Medicare primary specialty in Illinois — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Illinois College Of Med (chi/peor/rock/chm-Urb) |
| Graduation year | 1988 (38 years since medical school) |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1710179759 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians