Robert Blair Ash, MD
Radiation Oncology Physician · Orange, CA
Robert Blair Ash, MD is a radiation oncology physician with a practice address in Orange, California, and NPI 1326238650, issued on Aug 1, 2007. Check the license (California C52450, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Robert Blair Ash
- Credential
- MD
- Primary taxonomy
- Radiation Oncology Physician 2085R0001X
- License number
- C52450 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1000 W. Laveta Ave., Orange, CA 92868
- Phone
- (714) 734-6250
- Enumerated
- Aug 1, 2007
- Record last updated
- Nov 11, 2020 (not updated in 6 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20071022000552); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest radiation oncology physician records → All 735 in California → Look up another NPI →
Also registered at 1000 W. Laveta Ave.
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Tanuja Bhandari, MDRadiation Oncology Physician1518147610
- Venita Williams, MDRadiation Oncology Physician1659581775
Verify Robert Blair Ash in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license C52450Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
61% more Medicare Part D claims than the average radiation oncology physician in 2024
216 Medicare Part D claims for 106 beneficiaries, against an average of 134 among the 4,851 providers of this specialty who prescribed in Part D. Brand-name drugs were 18% of claims. 12 claims were for opioids.
Most prescribed
- Tamsulosin Hcl80 claims
- Ssd24 claims
- Lidocaine Hcl Viscous22 claims
- Silver Sulfadiazine15 claims
- Nystatin11 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): 99.1 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).
Industry payments in 2024: $22.63
1 payment: food and beverage; the largest payer was Siemens Medical Solutions USA, Inc. The 3,275 providers of this specialty with any payment received $1,897.85 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- City OF Hope Medical FoundationSouth Pasadena, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Robert Blair Ash among 735 radiation oncology physician records in California
Robert Blair Ash, MD is one of 735 radiation oncology physician records with a practice address in California. 83% 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 45% of them.
- NPI issued2007 · 45% of these records are older, 43% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 74% of these records are
- Graduated1995 · median 2005 among the 545 with a school on file
- Record last updated2020 · 55% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 2085R0001X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Radiation Oncology Physician providers in California
There are 735 radiation oncology physician records in California.
All 735 in California → Every provider in Orange → Radiation Oncology Physician nationwide →
The 8 radiation oncology physician records with the nearest ZIP codes
- Christina Abel, NURSE PRACTITIONEROrange, CA 928681033638911
- Tanuja Bhandari, MDOrange, CA 928681518147610
- Allen Chen, M.D.Orange, CA 928681518992981
- Megan Daly, M.D.Orange, CA 928681780863340
- Steven Davis, M.D.Orange, CA 928681558463653
- Shera Feinstein, MDOrange, CA 928681437600194
- Jeremy Harris, MDOrange, CA 928681922427053
- Erin Healy, MDOrange, CA 928681437407863
Common questions
What is Robert Blair Ash, MD's NPI number?
Robert Blair Ash, MD's National Provider Identifier (NPI) is 1326238650, issued on Aug 1, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Robert Blair Ash, MD located?
The NPPES record lists a practice address at 1000 W. Laveta Ave., Orange, CA, 92868. Phone: (714) 734-6250. Providers update this record themselves, so call before visiting.
How can I verify Robert Blair Ash, MD's license?
NPPES lists California license number C52450, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Robert Blair Ash, MD prescribe under Medicare Part D?
In 2024, Robert Blair Ash, MD had 216 Medicare Part D claims for 106 beneficiaries; the average among radiation oncology physician prescribers was 134. Part D covers Medicare prescriptions only.
What is Robert Blair Ash, MD's MIPS final score?
The 2023 MIPS final score is 99.1 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.