Gregory Isenberg, MD
Internal Medicine Physician · Hartford, CT
Gregory Isenberg, MD is an internal medicine physician with a practice address in Hartford, Connecticut, and NPI 1801909643, issued on Aug 16, 2006. Check the license (Connecticut 035473, as entered in NPPES) on the Connecticut Medical Examining Board; the Medicare figures below come from public CMS files.
- Name
- Gregory Isenberg
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 035473 CT
Self-reported in NPPES; status is on the state search - Practice location
- 580 Farmington Ave, Hartford, CT 06105
- Phone
- (860) 527-7255
- Enumerated
- Aug 16, 2006
- Record last updated
- Dec 17, 2012 (not updated in 14 years: call before relying on the address or phone)
- Fax
- (860) 278-3867
- Medicaid ID
- 001354737 CT
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 2,623 in Connecticut → Look up another NPI →
Also registered at 580 Farmington Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Karen Helfeld, KAREN ISRAELPhysical Therapist1790989903
- Marina SasonovPhysical Therapist1093800013
- Rebecca Schaffino Borges, RPTPhysical Therapist1790857282
Verify Gregory Isenberg in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersConnecticut Medical Examining Board
Search for license 035473Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
100% fewer Medicare Part D claims than the average internal medicine physician in 2024
12 Medicare Part D claims, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
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.
Gregory Isenberg among 2,623 internal medicine physician records in Connecticut
Gregory Isenberg, MD is one of 2,623 internal medicine physician records with a practice address in Connecticut. 81% 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 11% of them.
- NPI issued2006 · 11% of these records are older, 52% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileNo · 63% of these records are
- Record last updated2012 · 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 207R00000X and a Connecticut practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
169 internal medicine physician records list a practice address in Hartford
They are 169 of the 6,317 NPPES records with a practice address in Hartford, and 2,623 internal medicine physician records in Connecticut.
All 2,623 in Connecticut → Every provider in Hartford → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Luis Diez-Morales, MDHartford, CT 061051205838513
- Howard Grayson, MDHartford, CT 061051205813102
- Tracey Jablonski, MDHartford, CT 061051619133873
- Charles Kantor, MDHartford, CT 061051164468237
- Antarpreet KaurHartford, CT 061051952578643
- Jayapriya KrishnaswamyHartford, CT 061051639337827
- Ralph Martin, MDHartford, CT 061051760484083
- Danilo Pangilinan, MDHartford, CT 061051184691800
Common questions
What is Gregory Isenberg, MD's NPI number?
Gregory Isenberg, MD's National Provider Identifier (NPI) is 1801909643, issued on Aug 16, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Gregory Isenberg, MD located?
The NPPES record lists a practice address at 580 Farmington Ave, Hartford, CT, 06105. Phone: (860) 527-7255. Providers update this record themselves, so call before visiting.
How can I verify Gregory Isenberg, MD's license?
NPPES lists Connecticut license number 035473, as entered by the provider. Search the Connecticut Medical Examining Board at https://www.elicense.ct.gov/Lookup/LicenseLookup.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Gregory Isenberg, MD prescribe under Medicare Part D?
In 2024, Gregory Isenberg, MD had 12 Medicare Part D claims; the average among internal medicine physician prescribers was 3,176. 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.