Keith Marcus, MD
Internal Medicine Physician · Ludington, MI
Keith Marcus, MD is an internal medicine physician with a practice address in Ludington, Michigan, and NPI 1255371365, issued on Jun 7, 2006. Check the license (Michigan 4301050045, as entered in NPPES) on the Michigan Board of Medicine (LARA); the Medicare figures below come from public CMS files.
- Name
- Keith Marcus
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 4301050045 MI
Self-reported in NPPES; status is on the state search - Practice location
- 1 Atkinson Dr, Ludington, MI 49431
- Phone
- (616) 391-3139
- Enumerated
- Jun 7, 2006
- Record last updated
- Mar 1, 2024
- Medicare enrollment
- Enrolled (PECOS I20070919000668); accepts Medicare assignment
- Medical or professional school
- University Of Iowa, Rj & L Carver College Of Medicine, 1985
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 5,735 in Michigan → Look up another NPI →
Also registered at 1 Atkinson Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Holly Brooks, RNGeneral Practice Registered Nurse1659149102
- Sadie Buday, PA-CPhysician Assistant1407665771
- Kelly Buxman, RDRegistered Dietitian1477085827
- Catherine Czesnowski, M.D.Internal Medicine Physician1013399245
Verify Keith Marcus in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMichigan Board of Medicine (LARA)
Search for license 4301050045Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
89% fewer Medicare Part D claims than the average internal medicine physician in 2024
357 Medicare Part D claims for 118 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Pantoprazole Sodium23 claims
- Omeprazole17 claims
- Potassium Chloride15 claims
- Cefuroxime14 claims
- Prednisone14 claims
- Furosemide13 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.
Industry payments in 2024: $351.70
7 payments; by number, the most common kind was food and beverage; the largest payer was Galderma Laboratories, L.P. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Spectrum Health Primary Care PartnersKentwood, MI
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Keith Marcus among 5,735 internal medicine physician records in Michigan
Keith Marcus, MD is one of 5,735 internal medicine physician records with a practice address in Michigan. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 10% of them.
- NPI issued2006 · 10% of these records are older, 60% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 62% of these records are
- Graduated1985 · median 2006 among the 3,564 with a school on file
- Record last updated2024 · 54% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Michigan practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
9 internal medicine physician records list a practice address in Ludington
They are 9 of the 481 NPPES records with a practice address in Ludington, and 5,735 internal medicine physician records in Michigan.
All 5,735 in Michigan → Every provider in Ludington → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Joel Allotey, MDLudington, MI 494311376216507
- Ralph Avedisian, DOLudington, MI 494311316054125
- Amy Beeman, D.O.Ludington, MI 494311891743837
- Catherine Czesnowski, M.D.Ludington, MI 494311013399245
- Zane Knoer, DOLudington, MI 494311326155144
- Bryan Kovas, M.D.Ludington, MI 494311063684769
- Bobby Lee, MDLudington, MI 494311891767489
- Mary Ocallaghan, DOLudington, MI 494311558369884
Common questions
What is Keith Marcus, MD's NPI number?
Keith Marcus, MD's National Provider Identifier (NPI) is 1255371365, issued on Jun 7, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Keith Marcus, MD located?
The NPPES record lists a practice address at 1 Atkinson Dr, Ludington, MI, 49431. Phone: (616) 391-3139. Providers update this record themselves, so call before visiting.
How can I verify Keith Marcus, MD's license?
NPPES lists Michigan license number 4301050045, as entered by the provider. Search the Michigan Board of Medicine (LARA) at https://aca-prod.accela.com/MILARA/GeneralProperty/PropertyLookUp.aspx?isLicensee=Y&TabName=APO. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Keith Marcus, MD prescribe under Medicare Part D?
In 2024, Keith Marcus, MD had 357 Medicare Part D claims for 118 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.
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.