OPTUM
Medicare Clinicians for NPI 1891981502
Internal Medicine - Addiction Medicine in Tustin, CA
Clinicians Billing Medicare Through This Organization CMS
Clinicians who reassign their Medicare billing to this organization, per CMS enrollment records.
Optum in Tustin, CA bills Medicare for 2,044 clinicians across 51 Medicare specialties. The largest specialties are Internal Medicine with 612, Family Practice with 525 and Nurse Practitioner with 373. Of these, 190 practice within 10 miles. Search by name or filter by specialty; each name links to that clinician's NPI profile.
This page lists the 250 clinicians practicing nearest to this organization's location. All 2,044 are counted in the totals above.
Internal Medicine (63 of 612)
Fountain Valley, CA 92708
Family Practice (48 of 525)
Nurse Practitioner (33 of 373)
Physical Therapist in Private Practice (8 of 40)
Gastroenterology (6 of 19)
Fountain Valley, CA 92708
Laguna Hills, CA 92653
Hospitalist (6 of 46)
Obstetrics/Gynecology (6 of 41)
Fountain Valley, CA 92708
Otolaryngology (6 of 15)
Dermatology (5 of 25)
Laguna Hills, CA 92653
Neurology (5 of 35)
Anaheim, CA 92806
Pulmonary Disease (5 of 19)
Endocrinology (4 of 31)
Laguna Hills, CA 92653
Pediatric Medicine (4 of 42)
Emergency Medicine (3 of 20)
Hematology/Oncology (3 of 5)
Nephrology (3 of 10)
Laguna Hills, CA 92653
Laguna Hills, CA 92653
Orthopedic Surgery (3 of 13)
Podiatry (3 of 21)
Rheumatology (3 of 17)
Urology (3 of 8)
Anesthesiology (2 of 3)
Cardiovascular Disease (Cardiology) (2 of 12)
Critical Care (Intensivists) (2 of 6)
General Surgery (2 of 18)
Infectious Disease (2 of 5)
Ophthalmology (2 of 13)
Osteopathic Manipulative Medicine (2)
Sports Medicine (2 of 5)
Certified Nurse Midwife (CNM) (1 of 2)
Fountain Valley, CA 92708
Clinical Social Worker (1)
Diagnostic Radiology (1 of 5)
Geriatric Medicine (1 of 4)
Hospice/Palliative Care (1 of 9)
Interventional Cardiology (1)
Medical Oncology (1)
Neurosurgery (1)
Optometry (1 of 12)
Pain Management (1)
Physical Medicine and Rehabilitation (1 of 2)
Preventive Medicine (1)
Qualified Audiologist (1)
Registered Dietitian or Nutrition Professional (1 of 4)
About this data
Medicare reassignment. A clinician who works for a hospital, clinic or medical group usually signs a Medicare reassignment (form CMS-855R). It lets the organization bill Medicare for the clinician's services and receive the payment. This page lists the clinicians whose reassignment to Optum appears in the CMS Revalidation Reassignment List.
Who is included. Clinicians who bill Medicare under their own NPI through this organization. A clinician can reassign to more than one organization, so the same name may also appear under other groups.
Nearest 250. The totals and specialty counts cover all 2,044 clinicians. The list shows the 250 whose practice address is closest to this NPI's location, so each Optum location shows its own nearest clinicians.
Addresses and phone numbers come from each clinician's own NPPES record, so they may point to another office or to the clinician's own practice.
Source: CMS Revalidation Reassignment List, October 2026 release; addresses, phone numbers and Medicare status from NPPES and PECOS. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
