DR. LUKEJOHN WELCH DAY M.D.
NPI 1669623773
Internal Medicine - Gastroenterology in San Francisco, CA
About Dr. Lukejohn Welch Day M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. LUKEJOHN WELCH DAY M.D. (NPI 1669623773) is an individual gastroenterology provider in San Francisco, California, licensed in California (A93534) and active in the NPI registry since October 2008. He is enrolled in Medicare PECOS.
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. Lukejohn Welch Day M.d. is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignments
5Medicare enrollment records show Lukejohn Day reassigns Medicare billing to 5 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
San Francisco, CA 94143
- Reassigned Medicare billing, California enrollment
- 2,112 clinicians in this Medicare group
San Francisco, CA 94143
- Reassigned Medicare billing, California enrollment
- 5,645 clinicians in this Medicare group
San Francisco, CA 94122
- Reassigned Medicare billing, California enrollment
- 5,544 clinicians in this Medicare group
San Francisco, CA 94116
- Reassigned Medicare billing, California enrollment
- 1,573 clinicians in this Medicare group
San Francisco, CA 94110
- Reassigned Medicare billing, California enrollment
- 23 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.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 94143 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Medicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
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 Lukejohn Day's NPI number?
The NPI number for Lukejohn Day is 1669623773. It was assigned to this individual provider in the NPPES registry on October 7, 2008.
Where is Lukejohn Day located?
Lukejohn Day practices at 505 Parnassus Ave, San Francisco, CA 94143. The listed phone number is (415) 377-2176.
What is Lukejohn Day's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Gastroenterology, with taxonomy code 207RG0100X.
Is Lukejohn Day enrolled in Medicare?
Yes. Lukejohn Day is registered in the Medicare PECOS enrollment system.
Which organizations bill Medicare for Lukejohn Day's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Lukejohn Day reassigns Medicare benefits to 5 organizations: Regents Of The University Of California (San Francisco, CA), University Of California San Francisco (San Francisco, CA), Ucsf Medical Group Business Services (San Francisco, CA), City & County Of San Francisco (San Francisco, CA) and University Of California Sfgh Medical Group (San Francisco, CA). 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 Lukejohn Day'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 Lukejohn Day was last updated on October 7, 2008. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 18 years 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. Lukejohn Welch Day, M.D. · NPI 1669623773
Gastroenterology physician in San Francisco, California. Individual provider, active in the CMS NPPES registry since October 7, 2008.
## Identity
- **NPI:** 1669623773 (Entity type: Individual)
- **Enumerated:** October 7, 2008
- **Primary specialty:** Internal Medicine - Gastroenterology · taxonomy 207RG0100X
- **State license:** A93534 (California)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 505 PARNASSUS AVE, San Francisco, CA 94143-2204
- **Phone:** (415) 377-2176
## 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:** 5 organizations under Medicare reassignment (form CMS-855R): Regents Of The University Of California (NPI 1376613943, San Francisco, CA); University Of California San Francisco (NPI 1346329380, San Francisco, CA); Ucsf Medical Group Business Services (NPI 1477624104, San Francisco, CA); City & County Of San Francisco (NPI 1528083300, San Francisco, CA); University Of California Sfgh Medical Group (NPI 1578538609, San Francisco, CA) · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** October 7, 2008
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Source: [NPI Profile](https://npiprofile.com/npi/1669623773) · Data from the CMS NPPES public registry.