Dr. Karthikeyan Viswanathan DO
About this NPIWhat this record shows.
NPI 1396128336 is registered to Dr. Karthikeyan Viswanathan DO, a Internal Medicine practising at 4546 El Camino Real Ste B7 in Los Altos, California. Internal Medicine physicians (internists) specialise in the prevention, diagnosis, and treatment of diseases in adults, often coordinating care across multiple subspecialties. Dr. Karthikeyan Viswanathan DO has been enumerated in the National Provider Identifier (NPI) registry since 2015.
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Medicare enrollment
This provider holds 4 Medicare enrollments on file with the Provider Enrollment, Chain and Ownership System (PECOS). Each enrollment carries a public Medicare Enrollment ID (ENRLMT_ID) used by billers and intermediaries.
Practitioner
- I20200928001291Internal MedicineMP
- I20210113001821Internal MedicineTX
- I20230123001402Internal MedicineCA
- I20250116000720Family PracticeCA
Source: CMS PECOS public enrollment file.
Insurance & acceptsHow to confirm coverage.
The National Plan and Provider Enumeration System (NPPES) registry does not include commercial insurance network data, so we cannot show which plans Dr. Karthikeyan Viswanathan DO accepts. To confirm in-network status with your specific health plan, contact Dr. Karthikeyan Viswanathan DO directly at (866) 362-4246.
Frequently asked
Yes. NPI 1396128336 is registered as Active in the CMS NPPES public registry and passes the Luhn check-digit validation that all 10-digit NPIs use.
Internal Medicine physicians (internists) specialise in the prevention, diagnosis, and treatment of diseases in adults, often coordinating care across multiple subspecialties.
The CMS NPPES Public Registry at npiregistry.cms.hhs.gov is the authoritative source. FindMyNPI mirrors this dataset and refreshes monthly. For real-time verification, you can also call the provider's office at (866) 362-4246.
An individual healthcare provider has a single Type-1 NPI for life. Organisations can hold separate Type-2 NPIs per location, specialty, or sub-entity. Dr. Karthikeyan Viswanathan DO is a Type-1 individual NPI.