Dara Grennan
Infectious Disease Physician · Dixon, IL
Dara Grennan is an infectious disease physician with a practice address in Dixon, Illinois, and NPI 1518282938, issued on Mar 29, 2010. Check the license (Illinois 036-137502, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Dara Grennan
- Primary taxonomy
- Infectious Disease Physician 207RI0200X
- License numbers
- 036-137502 IL
36.137502 IL
8153445 UT
Self-reported in NPPES; status is on the state search - Practice location
- 403 E 1St St, Dixon, IL 61021
- Phone
- (815) 285-5629
- Enumerated
- Mar 29, 2010
- Record last updated
- Apr 26, 2021 (not updated in 5 years: call before relying on the address or phone)
- Fax
- (815) 285-5634
- Medicaid ID
- 036137502 IL
- Medicare enrollment
- Enrolled (PECOS I20171107000107); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest infectious disease physician records → All 464 in Illinois → Look up another NPI →
Also registered at 403 E 1St St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Andres Arellano, DPTPhysical Therapist1205458528
Verify Dara Grennan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersIllinois Department of Financial and Professional Regulation
Search for license 036-137502Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
5% fewer Medicare Part D claims than the average infectious disease physician in 2024
652 Medicare Part D claims for 29 beneficiaries, against an average of 689 among the 7,388 providers of this specialty who prescribed in Part D. 23 claims were for opioids.
Most prescribed
- Dovato66 claims
- Biktarvy65 claims
- Atorvastatin Calcium59 claims
- Gabapentin30 claims
- Prezcobix26 claims
- Albuterol Sulfate Hfa22 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.
The MIPS final score for 2023 (Medicare payment program): 94.1 of 100
The Merit-based Incentive Payment System score is reported for this clinician. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023; category weights for 2023 (qpp.cms.gov).
Bills Medicare through 2 group practices
- Cook CountyChicago, IL
- Northwestern Medical Faculty FoundationLake Forest, IL
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Dara Grennan among 464 infectious disease physician records in Illinois
Dara Grennan is one of 464 infectious disease physician records with a practice address in Illinois. 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 2010, is newer than 61% of them.
- NPI issued2010 · 61% of these records are older, 34% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 67% of these records are
- Graduated2007 · median 2004 among the 311 with a school on file
- Record last updated2021 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RI0200X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Infectious Disease Physician providers in Illinois
There are 464 infectious disease physician records in Illinois.
All 464 in Illinois → Every provider in Dixon → Infectious Disease Physician nationwide →
The 8 infectious disease physician records with the nearest ZIP codes
- Abdulhamid Alkhalaf, M.D.Dixon, IL 610211043237035
- Robert Geller, MDFreeport, IL 610321013983212
- Hussein Zaioor, MDSterling, IL 610811013919943
- Suma Rao, MDRockford, IL 611021346223294
- Moamen Al Zoubi, MDRockford, IL 611031770902587
- Scott Homann, M.D.Rockford, IL 611041689674541
- Geoffrey Tsaras, MDRockford, IL 611041023278769
- Jason Malenfant, M.D.Rockford, IL 611071578976411
Common questions
What is Dara Grennan's NPI number?
Dara Grennan's National Provider Identifier (NPI) is 1518282938, issued on Mar 29, 2010. An NPI identifies a provider in billing; it is not a license.
Where is Dara Grennan located?
The NPPES record lists a practice address at 403 E 1St St, Dixon, IL, 61021. Phone: (815) 285-5629. Providers update this record themselves, so call before visiting.
How can I verify Dara Grennan's license?
NPPES lists Illinois license number 036-137502, as entered by the provider. 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 Dara Grennan prescribe under Medicare Part D?
In 2024, Dara Grennan had 652 Medicare Part D claims for 29 beneficiaries; the average among infectious disease physician prescribers was 689. Part D covers Medicare prescriptions only.
What is Dara Grennan's MIPS final score?
The 2023 MIPS final score is 94.1 of 100. The average among 454,083 clinicians with a measured score was 83.5.
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.