Guerin T. Williams, PA
Physician Assistant · Chicago, IL
Guerin T. Williams, PA is a physician assistant with a practice address in Chicago, Illinois, and NPI 1750564787, issued on Dec 13, 2007. Check the license with the Illinois board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Guerin T. Williams
- Credential
- PA
- Primary taxonomy
- Physician Assistant 363A00000X
- Practice location
- 680 N Lake Shore Dr, Chicago, IL 60611
- Phone
- (312) 695-9797
- Enumerated
- Dec 13, 2007
- Record last updated
- Jan 18, 2008 (not updated in 18 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20080118000560); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
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A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Guerin T. Williams in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich Illinois board licenses this professionCheck the board
- 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
38% fewer Medicare Part D claims than the average physician assistant in 2024
512 Medicare Part D claims for 177 beneficiaries, against an average of 830 among the 101,058 providers of this specialty who prescribed in Part D. Brand-name drugs were 17% of claims.
Most prescribed
- Tamsulosin Hcl130 claims
- Cephalexin43 claims
- Gemtesa43 claims
- Myrbetriq38 claims
- Testosterone34 claims
- Trospium Chloride29 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 one group practice
- Northwestern Medical Faculty FoundationChicago, IL
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Guerin T. Williams among 4,926 physician assistant records in Illinois
Guerin T. Williams, PA is one of 4,926 physician assistant records with a practice address in Illinois. 82% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 12% of them.
- NPI issued2007 · 12% of these records are older, 83% newer
- In a Medicare fileYes · 82% of these records are
- In the CMS Doctors and Clinicians fileYes · 69% of these records are
- Graduated2004 · median 2019 among the 3,407 with a school on file
- Record last updated2008 · 35% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363A00000X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
1,445 physician assistant records list a practice address in Chicago
They are 1,445 of the 63,379 NPPES records with a practice address in Chicago, and 4,926 physician assistant records in Illinois.
All 4,926 in Illinois → Every provider in Chicago → Physician Assistant nationwide →
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Common questions
What is Guerin T. Williams, PA's NPI number?
Guerin T. Williams, PA's National Provider Identifier (NPI) is 1750564787, issued on Dec 13, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Guerin T. Williams, PA located?
The NPPES record lists a practice address at 680 N Lake Shore Dr, Chicago, IL, 60611. Phone: (312) 695-9797. Providers update this record themselves, so call before visiting.
How can I verify Guerin T. Williams, PA's license?
Search the Illinois board that licenses this profession; the NPPES record confirms identity only.
How much does Guerin T. Williams, PA prescribe under Medicare Part D?
In 2024, Guerin T. Williams, PA had 512 Medicare Part D claims for 177 beneficiaries; the average among physician assistant prescribers was 830. Part D covers Medicare prescriptions only.
What is Guerin T. Williams, PA'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.