Mark C O'brien, DO - Medicare Internal Medicine in Vista, CA

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Mark C O'brien, DO is a medicare enrolled "Internal Medicine" physician in Vista, California. He went to Michigan State University College Of Osteopathic Medicine and graduated in 1987 and has 38 years of diverse experience with area of expertise as Internal Medicine. His current practice location is 161 Thunder Dr Ste 210, Vista, California. You can reach out to his office (for appointments etc.) via phone at (760) 216-6500.

Mark C O'brien is licensed to practice in California (license number 20A6017) and he also participates in the medicare program. He accepts medicare assignments (which means he accepts the Medicare-approved amount; you will not be billed for any more than the Medicare deductible and coinsurance) and his NPI Number is 1497744247.

Contact Information

Mark C O'brien, DO
161 Thunder Dr Ste 210,
Vista, CA 92083-6052
(760) 216-6500
(760) 295-4753

Map and Direction




Physician's Profile

Full NameMark C O'brien
GenderMale
SpecialityInternal Medicine
Experience38 Years
Location161 Thunder Dr Ste 210, Vista, California
Accepts Medicare AssignmentsYes. He accepts the Medicare-approved amount; you will not be billed for any more than the Medicare deductible and coinsurance.
  Medical Education and Training:
  • Mark C O'brien attended and graduated from Michigan State University College Of Osteopathic Medicine in 1987
  NPI Data:
  • NPI Number: 1497744247
  • Provider Enumeration Date: 10/14/2005
  • Last Update Date: 04/01/2025
  Medicare PECOS Information:
  • PECOS PAC ID: 6103728118
  • Enrollment ID: I20080307000443

Medical Identifiers

Medical identifiers for Mark C O'brien such as npi, medicare ID, medicare PIN, medicaid, etc.
IdentifierTypeStateIssuer
1497744247NPI-NPPES

Medical Taxonomies and Licenses

TaxonomyTypeLicense (State)Status
207R00000XInternal Medicine 20A6017 (California)Primary

Medicare Reassignments

Some practitioners may not bill the customers directly but medicare billing happens through clinics / group practice / hospitals where the provider works. Medicare reassignment of benefits is a mechanism by which practitioners allow third parties to bill and receive payment for medicare services performed by them. Mark C O'brien allows following entities to bill medicare on his behalf.
Entity NameHospitalist Medicine Physicians Of California Inc
Entity TypePart B Supplier - Clinic/group Practice
Entity IdentifiersNPI Number: 1184663965
PECOS PAC ID: 8426062027
Enrollment ID: O20060202000956
Entity NameKansal Inc
Entity TypePart B Supplier - Clinic/group Practice
Entity IdentifiersNPI Number: 1043510183
PECOS PAC ID: 6406089739
Enrollment ID: O20140512001295
Entity NameInpatient Specialists Of California Pc
Entity TypePart B Supplier - Clinic/group Practice
Entity IdentifiersNPI Number: 1952792475
PECOS PAC ID: 3476864448
Enrollment ID: O20150617000915
Entity NameMark C Obrien Do Inc
Entity TypePart B Supplier - Clinic/group Practice
Entity IdentifiersNPI Number: 1346060860
PECOS PAC ID: 8820526171
Enrollment ID: O20250114002066

Medicare Part D Prescriber Enrollment

Any physician or other eligible professional who prescribes Part D drugs must either enroll in the Medicare program or opt out in order to prescribe drugs to their patients with Part D prescription drug benefit plans. Mark C O'brien is enrolled with medicare and thus, if eligible, can prescribe medicare part D drugs to patients with medicare part D benefits.

Mailing Address and Practice Location

Mailing AddressPractice Location Address
Mark C O'brien, DO
161 Thunder Dr Ste 210,
Vista, CA 92083-6052

Ph: (760) 216-6500		Mark C O'brien, DO
161 Thunder Dr Ste 210,
Vista, CA 92083-6052

Ph: (760) 216-6500

Reviews and Comments


Internal Medicine Doctors in Vista, CA

Leila Shabanian, M.D.
Internal Medicine
Medicare: Accepting Medicare Assignments
Practice Location: 1000 Vale Terrace Dr, Vista, CA 92084
Phone: 760-631-5000    Fax: 760-414-3892
Ted Wayne Gay, MD
Internal Medicine
Medicare: Not Enrolled in Medicare
Practice Location: 122 Escondido Avenue, Ste 101, Vista, CA 92084
Phone: 760-806-9263    Fax: 760-806-9264
Oscar A Matthews, M.D.
Internal Medicine
Medicare: Not Enrolled in Medicare
Practice Location: 2095 W Vista Way, #107, Vista, CA 92083
Phone: 760-941-4005    Fax: 760-941-4090
Rashad Ansari, MD
Internal Medicine
Medicare: May Accept Medicare Assignments
Practice Location: 2023 W Vista Way, Ste. J, Vista, CA 92083
Phone: 760-724-6100    
Stuart B Kipper, M.D.
Internal Medicine
Medicare: Accepting Medicare Assignments
Practice Location: 910 Sycamore Ave, Suite 220, Vista, CA 92081
Phone: 760-598-1700    Fax: 760-598-1196
Kristin Bell, M.D.
Internal Medicine
Medicare: Medicare Enrolled
Practice Location: 1840 West Dr, Vista, CA 92083
Phone: 858-552-8585    Fax: 760-945-6011
Dr. Franklin Galef, MD
Internal Medicine
Medicare: Medicare Enrolled
Practice Location: 2120 Thibodo Rd # 110, Vista, CA 92081
Phone: 760-806-5820    Fax: 760-598-8231

Medicare Program: Medicare is a federal government program which provides health insurance to people who are 65 or older. This program also covers certain younger people with disabilities (who receive Social Security Disability Insurance - SSDI), and people with End-Stage Renal Disease (permanent kidney failure requiring dialysis or a transplant, sometimes called ESRD.

Medicare Assignment: Assignment means that your doctor, provider, or supplier agrees (or is required by law) to accept the Medicare-approved amount as full payment for covered services. Most doctors, providers, and suppliers accept assignment, but you should always check to make sure. Participating providers have signed an agreement to accept assignment for all Medicare-covered services.

NPI Number: The National Provider Identifier (NPI) is a unique identification number for covered health care providers. The NPI must be used in lieu of legacy provider identifiers in the HIPAA standards transactions. Covered health care providers and all health plans and health care clearinghouses must use the NPIs in the administrative and financial transactions adopted under HIPAA (Health Insurance Portability and Accountability Act).

Our Data: Information on www.medicarelist.com is built using data sources published by Centers for Medicare & Medicaid Services (CMS) under Freedom of Information Act (FOIA). The information disclosed on the NPI Registry are FOIA-disclosable and are required to be disclosed under the FOIA and the eFOIA amendments to the FOIA. There is no way to 'opt out' or 'suppress' the NPPES record data for health care providers with active NPIs.