Sergio A. Diaz, MD
Internal Medicine Physician · Johnson City, TN
Sergio A. Diaz, MD is an internal medicine physician with a practice address in Johnson City, Tennessee, and NPI 1417138439, issued on Nov 19, 2007. Check the license (Tennessee 43908, as entered in NPPES) on the Tennessee Board of Medical Examiners; the Medicare figures below come from public CMS files.
- Name
- Sergio A. Diaz
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 43908 TN
Self-reported in NPPES; status is on the state search - Practice location
- 301 Med Tech Pkwy Ste 240, Johnson City, TN 37604
- Phone
- (423) 794-5520
- Enumerated
- Nov 19, 2007
- Record last updated
- Feb 14, 2025
- Fax
- (423) 282-6940
- Medicaid ID
- 1508669 TN
- Medicare enrollment
- Enrolled (PECOS I20081023000436); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 2,596 in Tennessee → Look up another NPI →
Also registered at 301 Med Tech Pkwy Ste 240
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Whitney Aultman, PHARMDPharmacist1588161368
- Britny Boswell Hall, FNPFamily Nurse Practitioner1376236992
Verify Sergio A. Diaz in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersTennessee Board of Medical Examiners
Search for license 43908Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
76% fewer Medicare Part D claims than the average internal medicine physician in 2024
750 Medicare Part D claims for 308 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 8% of claims. 92 claims were for opioids.
Most prescribed
- Cefdinir112 claims
- Ondansetron Odt77 claims
- Hydrocodone-Acetaminophen51 claims
- Prednisone45 claims
- Furosemide27 claims
- Amoxicillin-Clavulanate Potass26 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
- State OF Franklin Healthcare Associates, PLLCJohnson City, TN
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Sergio A. Diaz among 2,596 internal medicine physician records in Tennessee
Sergio A. Diaz, MD is one of 2,596 internal medicine physician records with a practice address in Tennessee. 80% 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 54% of them.
- NPI issued2007 · 54% of these records are older, 37% newer
- In a Medicare fileYes · 80% of these records are
- In the CMS Doctors and Clinicians fileYes · 66% of these records are
- Graduated1997 · median 2003 among the 1,705 with a school on file
- Record last updated2025 · 56% 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 Tennessee practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
125 internal medicine physician records list a practice address in Johnson City
They are 125 of the 3,807 NPPES records with a practice address in Johnson City, and 2,596 internal medicine physician records in Tennessee.
All 2,596 in Tennessee → Every provider in Johnson City → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Paul Brown, MDJohnson City, TN 376041326043167
- Matthew Cary, MDJohnson City, TN 376041306841440
- Keith Cook, MDJohnson City, TN 376041396740957
- Frank Forbush, MDJohnson City, TN 376041538164660
- Mary Gibson, MDJohnson City, TN 376041164427290
- Michael Grosserode, MDJohnson City, TN 376041710982848
- Christopher Hemphill, MDJohnson City, TN 376041053316232
- Randy Hoover, MDJohnson City, TN 376041255336434
Common questions
What is Sergio A. Diaz, MD's NPI number?
Sergio A. Diaz, MD's National Provider Identifier (NPI) is 1417138439, issued on Nov 19, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Sergio A. Diaz, MD located?
The NPPES record lists a practice address at 301 Med Tech Pkwy Ste 240, Johnson City, TN, 37604. Phone: (423) 794-5520. Providers update this record themselves, so call before visiting.
How can I verify Sergio A. Diaz, MD's license?
NPPES lists Tennessee license number 43908, as entered by the provider. Search the Tennessee Board of Medical Examiners at https://www.tn.gov/health/licensure/me.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Sergio A. Diaz, MD prescribe under Medicare Part D?
In 2024, Sergio A. Diaz, MD had 750 Medicare Part D claims for 308 beneficiaries; 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.