DR. KARTHIKEYAN VISWANATHAN DO
NPI 1396128336
Internal Medicine in Los Altos, CA
About Dr. Karthikeyan Viswanathan Do NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. KARTHIKEYAN VISWANATHAN DO (NPI 1396128336) is an individual internal medicine provider in Los Altos, California, licensed in California (20A19044) and active in the NPI registry since July 2015. He is enrolled in Medicare PECOS and is a graduate of Other (2014).
NPPES Registry Identity
Specialties & Licenses
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare (PECOS)
Dr. Karthikeyan Viswanathan Do is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignments
6Medicare enrollment records show Karthikeyan Viswanathan reassigns Medicare billing to 6 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Los Altos, CA 94022
- Reassigned Medicare billing, California enrollment
- 19 clinicians in this Medicare group
Covelo, CA 95428
- Reassigned Medicare billing, California enrollment
- 31 clinicians in this Medicare group
Garberville, CA 95542
- Reassigned Medicare billing, California enrollment
- 89 clinicians in this Medicare group
Eureka, CA 95501
- Reassigned Medicare billing, California enrollment
- 55 clinicians in this Medicare group
Teecnospos, AZ 86514
- Reassigned Medicare billing, Texas enrollment
- 572 clinicians in this Medicare group
Saipan, MP 96950
- Reassigned Medicare billing, Northern Mariana Islands enrollment
- 4 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 2
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 94022 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Other Providers at the Same Location NPPES 13
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
LOS ALTOS, CA 94022
LOS ALTOS, CA 94022
LOS ALTOS, CA 94022
LOS ALTOS, CA 94022
LOS ALTOS, CA 94022
LOS ALTOS, CA 94022
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Karthikeyan Viswanathan's NPI number?
The NPI number for Karthikeyan Viswanathan is 1396128336. It was assigned to this individual provider in the NPPES registry on July 8, 2015.
Where is Karthikeyan Viswanathan located?
Karthikeyan Viswanathan practices at 4546 El Camino Real Ste B7, Los Altos, CA 94022. The listed phone number is (866) 362-4246.
What is Karthikeyan Viswanathan's specialty?
The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.
Is Karthikeyan Viswanathan enrolled in Medicare?
Yes. Karthikeyan Viswanathan is registered in the Medicare PECOS enrollment system.
Which organizations bill Medicare for Karthikeyan Viswanathan's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Karthikeyan Viswanathan reassigns Medicare benefits to 6 organizations: Integrative Behavioral Health & Medicine, Inc. (Los Altos, CA), Round Valley Indian Health Center, Inc. (Covelo, CA), Southern Humboldt Community Healthcare District (Garberville, CA), United Indian Health Services, Inc. (Eureka, CA), Dhhs, Phs, Naihs, Shiprock Hospital (Teecnospos, AZ) and 1 more organization, listed in the Medicare section above. Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Karthikeyan Viswanathan's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
When was this NPI record last updated?
The NPPES record for Karthikeyan Viswanathan was last updated on August 21, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 14 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Dr. Karthikeyan Viswanathan, DO · NPI 1396128336
Internal Medicine physician in Los Altos, California. Individual provider, active in the CMS NPPES registry since July 8, 2015.
## Identity
- **NPI:** 1396128336 (Entity type: Individual)
- **Enumerated:** July 8, 2015
- **Primary specialty:** Internal Medicine · taxonomy 207R00000X
- **State license:** 20A19044 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 4546 EL CAMINO REAL STE B7, Los Altos, CA 94022-1069
- **Phone:** (866) 362-4246 · **Fax:** (650) 260-6030
## Medicare
- **Medicare:** Enrolled in Medicare (PECOS)
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 6 organizations under Medicare reassignment (form CMS-855R): Integrative Behavioral Health & Medicine, Inc. (NPI 1548910151, Los Altos, CA); Round Valley Indian Health Center, Inc. (NPI 1669532750, Covelo, CA); Southern Humboldt Community Healthcare District (NPI 1336367515, Garberville, CA); United Indian Health Services, Inc. (NPI 1841986684, Eureka, CA); Dhhs, Phs, Naihs, Shiprock Hospital (NPI 1477615789, Teecnospos, AZ); and 1 more · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2014
## Record status
- **NPPES last updated:** August 21, 2025
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Source: [NPI Profile](https://npiprofile.com/npi/1396128336) · Data from the CMS NPPES public registry.