Katherine Siobhan Rivest, PA-C
Medical Physician Assistant · Easthampton, MA
Katherine Siobhan Rivest, PA-C is a medical physician assistant with a practice address in Easthampton, Massachusetts, and NPI 1164766226, issued on Nov 15, 2012. Check the license (Massachusetts PA4575, as entered in NPPES) with the Massachusetts board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Katherine Siobhan Rivest
- Credential
- PA-C
- Primary taxonomy
- Medical Physician Assistant 363AM0700X
- License number
- PA4575 MA
Self-reported in NPPES; status is on the state search - Practice location
- 2 Mechanic St, Easthampton, MA 01027
- Phone
- (413) 529-9282
- Enumerated
- Nov 15, 2012
- Record last updated
- Jan 12, 2016 (not updated in 10 years: call before relying on the address or phone)
- Fax
- (413) 527-7526
- Medicare enrollment
- Enrolled (PECOS I20140417002043); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest medical physician assistant records → All 886 in Massachusetts → Look up another NPI →
Also registered at 2 Mechanic St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Nataly Alicea-PastranaCounselor1770110363
- Jude Almeida-Merrell, MSW, LICSWClinical Social Worker1821255324
- James AtchleyMental Health Counselor1902613979
- Angelique AyalaCounselor1427931906
- Kristopher BanksCounselor1770478802
- Christine Beluzo, LMHCMental Health Counselor1255513339
Verify Katherine Siobhan Rivest in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich Massachusetts board licenses this profession
Search for license PA4575Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
91% fewer Medicare Part D claims than the average medical physician assistant in 2024
108 Medicare Part D claims for 75 beneficiaries, against an average of 1,148 among the 23,801 providers of this specialty who prescribed in Part D.
Most prescribed
- Azithromycin18 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): 97 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
- Western Mass Physician Associates IncHolyoke, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Katherine Siobhan Rivest among 886 medical physician assistant records in Massachusetts
Katherine Siobhan Rivest, PA-C is one of 886 medical physician assistant records with a practice address in Massachusetts. 78% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2012, is newer than 44% of them.
- NPI issued2012 · 44% of these records are older, 53% newer
- In a Medicare fileYes · 78% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2012 · median 2015 among the 559 with a school on file
- Record last updated2016 · 53% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363AM0700X and a Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Medical Physician Assistant providers in Massachusetts
There are 886 medical physician assistant records in Massachusetts.
All 886 in Massachusetts → Every provider in Easthampton → Medical Physician Assistant nationwide →
The 8 medical physician assistant records with the nearest ZIP codes
- Elisabeth BorkowskiEasthampton, MA 010271154192854
- Sara Rider, PACEasthampton, MA 010271336246586
- Rebecca Bailey, PA-CEast Longmeadow, MA 010281770039174
- Ashley Krupa, PA-CEast Longmeadow, MA 010281629811336
- Emiley Krupa, PA-CFeeding Hills, MA 010301962245688
- Amanda Horn, PA-CChicopee, MA 010201770121162
- Nisha MalikChicopee, MA 010201750949509
- Kelly McGuinness, PA-CChicopee, MA 010201730012832
Common questions
What is Katherine Siobhan Rivest, PA-C's NPI number?
Katherine Siobhan Rivest, PA-C's National Provider Identifier (NPI) is 1164766226, issued on Nov 15, 2012. An NPI identifies a provider in billing; it is not a license.
Where is Katherine Siobhan Rivest, PA-C located?
The NPPES record lists a practice address at 2 Mechanic St, Easthampton, MA, 01027. Phone: (413) 529-9282. Providers update this record themselves, so call before visiting.
How can I verify Katherine Siobhan Rivest, PA-C's license?
NPPES lists Massachusetts license number PA4575, as entered by the provider. Search the Massachusetts board that licenses this profession; the NPPES record confirms identity only.
How much does Katherine Siobhan Rivest, PA-C prescribe under Medicare Part D?
In 2024, Katherine Siobhan Rivest, PA-C had 108 Medicare Part D claims for 75 beneficiaries; the average among medical physician assistant prescribers was 1,148. Part D covers Medicare prescriptions only.
What is Katherine Siobhan Rivest, PA-C's MIPS final score?
The 2023 MIPS final score is 97 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.