Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Charles Yin-Yat Lo, MD

Surgery Physician in San Francisco, CA · enumerated 2005.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1811978604

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Registry record

Entity type Individual (Type 1)

Name Dr. Charles Yin-Yat Lo

Credential MD

Sex Male

Practice address San Francisco, CA, 94133

Phone (415) 391-9993

Fax (415) 291-9993

Enumeration date Nov 8, 2005

Last updated in NPPES Oct 29, 2024

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

208600000X Surgery Physician Allopathic & Osteopathic Physicians · License 00A519440 (CA) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier	Type	State	Issuer
00A519440	Medicaid	CA	-

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

How do I verify Charles Lo's NPI record?

Cross-check NPI 1811978604 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Is NPI 1811978604 active?

Yes, as of the latest NPPES snapshot, NPI 1811978604 is active (record last updated 2024-10-29).

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2024-10-29.