Registry data as of Aug 27, 2026

Mary Koumas, D.O.

Family Medicine Physician · Lake Forest, CA

Mary Koumas, D.O. is a family medicine physician with a practice address in Lake Forest, California, and NPI 1306838909, issued on Aug 19, 2005. Check the license (California 20A4402, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.

Record from CMS NPPES, loaded Aug 27, 2026 · Medicare files 2023 and 2024 · method · Verify with CMS →

NPPES recordas of Aug 27, 2026
1306838909
Name
Mary Koumas
Credential
D.O.
Primary taxonomy
Family Medicine Physician 207Q00000X
License number
20A4402 CA
Self-reported in NPPES; status is on the state search
Practice location
24401 Muirlands Blvd, Lake Forest, CA 92630
Phone
(949) 770-1950
Enumerated
Aug 19, 2005
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). A record is not a license: verify it with the state board.
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Also registered at 24401 Muirlands Blvd

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

  1. Paula HambletonGeneral Practice Dentistry1144357500
  2. Kathy Mortazavi, DDSDentist1851532626

Verify Mary Koumas in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of California
    Search for license 20A4402
    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 California license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

Statewide context: the Medical Board of California reported 374 disciplinary actions in FY 2022-23. California discipline data →

55% fewer Medicare Part D claims than the average family medicine physician in 2024

1,566 Medicare Part D claims for 138 beneficiaries, against an average of 3,519 among the 111,126 providers of this specialty who prescribed in Part D. 16 claims were for opioids.

  1. Mary Koumas1,566
  2. Specialty average3,519

Most prescribed

  1. Levothyroxine Sodium116 claims
  2. Atorvastatin Calcium102 claims
  3. Simvastatin65 claims
  4. Losartan Potassium61 claims
  5. Omeprazole45 claims
  6. Metformin Hcl Er41 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.

One hospital or facility affiliation

  1. Lake Forest Medical Group, Inc.Lake Forest, CA

Source: CMS Doctors and Clinicians affiliations; Hospital General Information (Care Compare) (data.cms.gov). Star ratings are CMS hospital ratings, not ratings of this provider.

14 family medicine physician records list a Lake Forest practice address

They are 14 of the 1,008 NPPES records with a Lake Forest practice address, and 16,272 family medicine physician records in California.

Other family medicine physician records in California

  1. Omer Aba-Omer, MDSanta Monica, CA1649702093
  2. Michelle Ababa, MDWilmington, CA1710922513
  3. Anna Tzeitel Abalos, MDRoseville, CA1720200017
  4. Adan Abarca, MDAnaheim, CA1760553689
  5. Vanessa Abarca, DOVentura, CA1952040859
  6. Lorraine Abate, M.D.Sacramento, CA1104840008
  7. Robert Abatecola, MDCastro Valley, CA1669551719
  8. Romeo Abaya, M.D.Cottonwood, CA1598053506
  9. Effiem Abbah, MD, MPHSan Francisco, CA1821185133
  10. Khuzeman Abbasi, MDSanta Rosa, CA1841979952

Common questions

What is Mary Koumas, D.O.'s NPI number?

Mary Koumas, D.O.'s National Provider Identifier (NPI) is 1306838909, issued on Aug 19, 2005. An NPI identifies a provider in billing; it is not a license.

Where is Mary Koumas, D.O. located?

The NPPES record lists a practice address at 24401 Muirlands Blvd, Lake Forest, CA, 92630. Phone: (949) 770-1950. Providers update this record themselves, so call before visiting.

How can I verify Mary Koumas, D.O.'s license?

NPPES lists California license number 20A4402, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does Mary Koumas, D.O. prescribe under Medicare Part D?

In 2024, Mary Koumas, D.O. had 1,566 Medicare Part D claims for 138 beneficiaries; the average among family medicine physician prescribers was 3,519. Part D covers Medicare prescriptions only.

Source: CMS National Plan and Provider Enumeration System (NPPES), loaded Aug 27, 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.

Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 27, 2026.