Registry data as of Aug 27, 2026

Claire Oosterbaan, DO

Family Medicine Physician · Chicago, IL

Claire Oosterbaan, DO is a family medicine physician with a practice address in Chicago, Illinois, and NPI 1083309918, issued on Apr 6, 2023. Check the license on the Illinois Department of Financial and Professional Regulation; 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
1083309918
Name
Claire Oosterbaan
Credential
DO
Primary taxonomy
Family Medicine Physician 207Q00000X
Practice location
4600 N Ravenswood Ave, Chicago, IL 60640
Phone
(773) 561-7500
Enumerated
Apr 6, 2023
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 4600 N Ravenswood Ave

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

  1. Brandon Bautista, DOFamily Medicine Physician1619727013
  2. Tiffany BlacklidgeStudent in an Organized Health Care Education/Training Program1235959511
  3. Jacob Broadrick, MSN RNRegistered Nurse1598576860
  4. Shannon BurkeFamily Medicine Physician1992682991
  5. Mariela Cano, M.D.Family Medicine Physician1053342204
  6. Diana Chavez, DOStudent in an Organized Health Care Education/Training Program1225731391

Verify Claire Oosterbaan in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersIllinois Department of Financial and Professional RegulationCheck 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 Illinois 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.

92% fewer Medicare Part D claims than the average family medicine physician in 2024

271 Medicare Part D claims for 42 beneficiaries, against an average of 3,519 among the 111,126 providers of this specialty who prescribed in Part D.

  1. Claire Oosterbaan271
  2. Specialty average3,519

Most prescribed

  1. Atorvastatin Calcium36 claims
  2. Amlodipine Besylate15 claims
  3. Gabapentin14 claims
  4. Levothyroxine Sodium12 claims
  5. Lisinopril12 claims
  6. Hydrochlorothiazide11 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.

1,497 family medicine physician records list a Chicago practice address

They are 1,497 of the 63,379 NPPES records with a Chicago practice address, and 5,925 family medicine physician records in Illinois.

Other family medicine physician records in Illinois

  1. Jon Aagaard, MDWheaton, IL1750496923
  2. Napoleon Abando, MDWoodstock, IL1003972753
  3. Nikka Abaricia, MDChicago, IL1790366342
  4. Mohemmed AbbasChicago, IL1609612522
  5. Muhammad AbbasAlton, IL1588341556
  6. Syed AbbasWest Dundee, IL1972733103
  7. Stefanie AbbottMaywood, IL1861137457
  8. Roann Abdeladl, MDEvanston, IL1437087103
  9. Ashraf Abdeljaber, M.DNormal, IL1023472636
  10. Ahmed Abdelkader, MDChicago, IL1659104230

Common questions

What is Claire Oosterbaan, DO's NPI number?

Claire Oosterbaan, DO's National Provider Identifier (NPI) is 1083309918, issued on Apr 6, 2023. An NPI identifies a provider in billing; it is not a license.

Where is Claire Oosterbaan, DO located?

The NPPES record lists a practice address at 4600 N Ravenswood Ave, Chicago, IL, 60640. Phone: (773) 561-7500. Providers update this record themselves, so call before visiting.

How can I verify Claire Oosterbaan, DO's license?

Search the Illinois Department of Financial and Professional Regulation at https://idfpr.illinois.gov/checklicense.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does Claire Oosterbaan, DO prescribe under Medicare Part D?

In 2024, Claire Oosterbaan, DO had 271 Medicare Part D claims for 42 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.