NPPES file of Aug 9, 2026

Stefan G. Karos, M.D.

Urology Physician · Leominster, MA

Stefan G. Karos, M.D. is a urology physician with a practice address in Leominster, Massachusetts, and NPI 1376530378, issued on Oct 4, 2005. Check the license (Massachusetts 73838, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1376530378
Name
Stefan G. Karos
Credential
M.D.
Primary taxonomy
Urology Physician 208800000X
License number
73838 MA
Self-reported in NPPES; status is on the state search
Practice location
50 Memorial Dr, Leominster, MA 01453
Phone
(978) 466-4075
Enumerated
Oct 4, 2005
Record last updated
Jun 18, 2021 (not updated in 5 years: call before relying on the address or phone)
Medicaid IDs
9713930 MA
3079465 MA
Medicare enrollment
Enrolled (PECOS I20050829000568); accepts Medicare assignment
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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Also registered at 50 Memorial Dr

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Shabbir Abbasi, M.D.Neurology Physician1992798797
  2. Lloyd Alderson, M.D.Neurology Physician1053368787
  3. John Aney, MDPsychiatry Physician1104901016
  4. Rebecca Aslam, R.D.Registered Dietitian1770982340
  5. William Brodkin, M.D.Internal Medicine Physician1457468670
  6. Jung-Ming Chen, M.D.Personal Emergency Response Attendant1588620322

Verify Stefan G. Karos in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
    Search for license 73838    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the Massachusetts license search

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64% fewer Medicare Part D claims than the average urology physician in 2024

488 Medicare Part D claims for 148 beneficiaries, against an average of 1,340 among the 10,782 providers of this specialty who prescribed in Part D. 23 claims were for opioids.

  1. Stefan Karos488
  2. Specialty average1,340

Most prescribed

  1. Tamsulosin Hcl160 claims
  2. Finasteride151 claims
  3. Ciprofloxacin Hcl40 claims
  4. Oxybutynin Chloride25 claims
  5. Doxazosin Mesylate23 claims
  6. Oxycodone-Acetaminophen23 claims

Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.

Urology Physician providers in Massachusetts

There are 377 urology physician records in Massachusetts.

All 377 in Massachusetts → Every provider in Leominster →

Other urology physician records in Massachusetts

  1. Joseph Adolph, MDMarlboro, MA1700883535
  2. Abdulsalam Albalawi, MDChestnut Hill, MA1487087375
  3. Mehrdad AlemozaffarBoston, MA1376749861
  4. Richard Alexander, M.D.Greenfield, MA1497762884
  5. Farshid Alizadeh, MDBrighton, MA1619608577
  6. Christopher Allard, MDBoston, MA1629486022
  7. Richard Altman, MDChelmsford, MA1134199748
  8. Joshua Altschuler, MDWorcester, MA1003471962
  9. Kevin Asher, MDSpringfield, MA1578733457
  10. Philip Ayvazian, MDWorcester, MA1487654984

Common questions

What is Stefan G. Karos, M.D.'s NPI number?

Stefan G. Karos, M.D.'s National Provider Identifier (NPI) is 1376530378, issued on Oct 4, 2005. An NPI identifies a provider in billing; it is not a license.

Where is Stefan G. Karos, M.D. located?

The NPPES record lists a practice address at 50 Memorial Dr, Leominster, MA, 01453. Phone: (978) 466-4075. Providers update this record themselves, so call before visiting.

How can I verify Stefan G. Karos, M.D.'s license?

NPPES lists Massachusetts license number 73838, as entered by the provider. Search the Massachusetts Board of Registration in Medicine at https://findmydoctor.mass.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does Stefan G. Karos, M.D. prescribe under Medicare Part D?

In 2024, Stefan G. Karos, M.D. had 488 Medicare Part D claims for 148 beneficiaries; the average among urology physician prescribers was 1,340. Part D covers Medicare prescriptions only.

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.

Written with AI tools from the named public files; every figure is computed from those files (how it is made).

Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.