Derek R. Illastron, MD
Internal Medicine Physician · Kahului, HI
Derek R. Illastron, MD is an internal medicine physician with a practice address in Kahului, Hawaii, and NPI 1790949956, issued on Jul 16, 2008. Check the license (Hawaii MD-18353, as entered in NPPES) on the Hawaii Medical Board; the Medicare figures below come from public CMS files.
- Name
- Derek R. Illastron
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License numbers
- MD-18353 HI
235414 MA
Self-reported in NPPES; status is on the state search - Practice location
- 110 E Kaahumanu Ave, Kahului, HI 96732
- Phone
- (808) 242-6464
- Enumerated
- Jul 16, 2008
- Record last updated
- Mar 19, 2019 (not updated in 7 years: call before relying on the address or phone)
- Fax
- (808) 243-2367
- Medicare enrollment
- Enrolled (PECOS I20160504002708); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 902 in Hawaii → Look up another NPI →
Also registered at 110 E Kaahumanu Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Ellecia Cook, D.O.Dermatology Physician1831422906
- Jalin Finai, AUDAudiologist1710502331
- Ryan Fusato, M.D.Internal Medicine Physician1578580296
- Jaydee GironOtolaryngology Physician1871166876
- Edie Hamilton, PA-CPhysician Assistant1992001432
Verify Derek R. Illastron in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersHawaii Medical Board
Search for license MD-18353Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
95% fewer Medicare Part D claims than the average internal medicine physician in 2024
146 Medicare Part D claims for 57 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Amoxicillin-Clavulanate Potass12 claims
- Atorvastatin Calcium12 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 practice group's MIPS final score for 2023 (Medicare payment program): 87 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. 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, group reporting; category weights for 2023 (qpp.cms.gov).
Bills Medicare through one group practice
- Hawaii Permanente Medical Group IncWailuku, HI
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Derek R. Illastron among 902 internal medicine physician records in Hawaii
Derek R. Illastron, MD is one of 902 internal medicine physician records with a practice address in Hawaii. 71% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2008, is newer than 57% of them.
- NPI issued2008 · 57% of these records are older, 40% newer
- In a Medicare fileYes · 71% of these records are
- In the CMS Doctors and Clinicians fileYes · 54% of these records are
- Graduated2005 · median 2001 among the 491 with a school on file
- Record last updated2019 · 63% 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 Hawaii practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Internal Medicine Physician providers in Hawaii
There are 902 internal medicine physician records in Hawaii.
All 902 in Hawaii → Every provider in Kahului → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Abdiel Angeles, M.D.Kahului, HI 967321295892081
- Reginald Buesa, MDKahului, HI 967321295787216
- Ryan Fusato, M.D.Kahului, HI 967321578580296
- Kevin Kato, M.D.Kahului, HI 967321649238114
- Gerard Livaudais, MDKahului, HI 967321376626283
- Jason Hughes, DOKahuku, HI 967311114194073
- Sally Chang, M.D.Kailua, HI 967341528041621
- Helen Ing, M.D.Kailua, HI 967341346290947
Common questions
What is Derek R. Illastron, MD's NPI number?
Derek R. Illastron, MD's National Provider Identifier (NPI) is 1790949956, issued on Jul 16, 2008. An NPI identifies a provider in billing; it is not a license.
Where is Derek R. Illastron, MD located?
The NPPES record lists a practice address at 110 E Kaahumanu Ave, Kahului, HI, 96732. Phone: (808) 242-6464. Providers update this record themselves, so call before visiting.
How can I verify Derek R. Illastron, MD's license?
NPPES lists Hawaii license number MD-18353, as entered by the provider. Search the Hawaii Medical Board at https://cca.hawaii.gov/pvl/boards/medical/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Derek R. Illastron, MD prescribe under Medicare Part D?
In 2024, Derek R. Illastron, MD had 146 Medicare Part D claims for 57 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
What is Derek R. Illastron, MD's MIPS final score?
The 2023 MIPS final score is 87 of 100, reported for the practice group. 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.