NPPES file of Aug 9, 2026

Darin O'Connor Harnisch, M.D.

Specialist · Niles, IL

Darin O'Connor Harnisch, M.D. is a specialist with a practice address in Niles, Illinois, and NPI 1710910880, issued on Jul 9, 2006. Check the license (Illinois 036-106895, as entered in NPPES) with the Illinois board that licenses this profession; 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
1710910880
Name
Darin O'Connor Harnisch
Credential
M.D.
Primary taxonomy
Specialist 174400000X
License number
036-106895 IL
Self-reported in NPPES; status is on the state search
Practice location
7900 N Milwaukee Ave, Niles, IL 60714
Phone
(847) 663-9400
Enumerated
Jul 9, 2006
Record last updated
Dec 20, 2021 (not updated in 5 years: call before relying on the address or phone)
Fax
(847) 663-9827
Medicare enrollment
Enrolled (PECOS I20040701000128); may accept Medicare assignment
Medical or professional school
Loyola University Of Chicago, Stritch School Of Medicine, 1998
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 7900 N Milwaukee Ave

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

  1. Kayla Barango, MSN, APRN, FNP-CFamily Nurse Practitioner1912676123
  2. Ellen Brull, M.D.Family Medicine Physician1043396419
  3. Donna DziengielPharmacist1598114209
  4. Juan Engel, MDGastroenterology Physician1225122393
  5. Walter Falkowski, MDUrology Physician1124067335
  6. Debra Haley, PHDClinical Psychologist1306948690

Verify Darin O'Connor Harnisch in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersWhich Illinois board licenses this profession
    Search for license 036-106895
    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
Find the Illinois license search

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72% fewer Medicare Part D claims than the average specialist in 2024

382 Medicare Part D claims for 94 beneficiaries, against an average of 1,380 among the 8,233 providers of this specialty who prescribed in Part D. Brand-name drugs were 30% of claims.

  1. Darin Harnisch382
  2. Specialty average1,380

Most prescribed

  1. Doxycycline Hyclate60 claims
  2. Descovy27 claims
  3. Cefadroxil24 claims
  4. Amoxicillin-Clavulanate Potass19 claims
  5. Ethambutol Hcl18 claims
  6. Rifampin18 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.

Bills Medicare through one group practice

  1. Northwest Infectious Disease Consultants, S.C.Niles, IL

Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).

Darin O'Connor Harnisch among 1,154 specialist records in Illinois

Darin O'Connor Harnisch, M.D. is one of 1,154 specialist records with a practice address in Illinois. 19% 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 8% of them.

  • NPI issued2006 · 8% of these records are older, 58% newer
  • In a Medicare fileYes · 19% of these records are
  • In the CMS Doctors and Clinicians fileYes · 11% of these records are
  • Graduated1998 · median 1988 among the 127 with a school on file
  • Record last updated2021 · 84% of these records were not updated in five years or more

Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 174400000X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).

Specialist providers in Illinois

There are 1,154 specialist records in Illinois.

The 8 specialist records with the nearest ZIP codes

  1. Marjerie Badilla, M.D.Niles, IL 607141467552653
  2. Eileen Dugan, LCSWLincolnwood, IL 607121538292875
  3. Nicole Hroma, SENIOR PTElmwood Park, IL 607071912050097
  4. Darlene Kelly, CTRSChicago, IL 607071508156381
  5. Amanda Loomis, CTRSChicago, IL 607071710271952
  6. Terry Stanek, MSPTElmwood Park, IL 607071972673150
  7. Linda Dudek-Francis, D.N.Harwood Heights, IL 607061699893842
  8. Ralph Francis, D.N.Harwood Heights, IL 607061558489708

Common questions

What is Darin O'Connor Harnisch, M.D.'s NPI number?

Darin O'Connor Harnisch, M.D.'s National Provider Identifier (NPI) is 1710910880, issued on Jul 9, 2006. An NPI identifies a provider in billing; it is not a license.

Where is Darin O'Connor Harnisch, M.D. located?

The NPPES record lists a practice address at 7900 N Milwaukee Ave, Niles, IL, 60714. Phone: (847) 663-9400. Providers update this record themselves, so call before visiting.

How can I verify Darin O'Connor Harnisch, M.D.'s license?

NPPES lists Illinois license number 036-106895, as entered by the provider. Search the Illinois board that licenses this profession; the NPPES record confirms identity only.

How much does Darin O'Connor Harnisch, M.D. prescribe under Medicare Part D?

In 2024, Darin O'Connor Harnisch, M.D. had 382 Medicare Part D claims for 94 beneficiaries; the average among specialist prescribers was 1,380. 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.