DR. COLIN E DIFFIE MD
NPI 1942616404
Internal Medicine - Rheumatology in Saint Louis, MO
About Dr. Colin E Diffie Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. COLIN E DIFFIE MD (NPI 1942616404) is an individual rheumatology provider in Saint Louis, Missouri, licensed in Missouri (2019017299) and active in the NPI registry since July 2014. He is enrolled in Medicare PECOS, is affiliated with Memorial Hospital, and maintains a secondary practice location in Saint Louis.
NPPES Registry Identity
Specialties & Licenses 2
Secondary Practice Location 1
Other Identifiers 1
Accepted Insurance
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Dr. Colin E Diffie Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignment
Medicare enrollment records show Colin Diffie reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Saint Louis, MO 63110
- Reassigned Medicare billing, Missouri enrollment
- 1,133 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 13
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.
Hospital Affiliations CMS Care Compare 5
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Memorial Hospital
Acute Care Hospitals · Belleville, ILBarnes Jewish Hospital
Acute Care Hospitals · Saint Louis, MOMissouri Baptist Medical Center
Acute Care Hospitals · Town And Country, MOBarnes-Jewish West County Hospital
Acute Care Hospitals · Creve Coeur, MOParkland Health Center
Acute Care Hospitals · Farmington, MOPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 63106 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.
SAINT LOUIS, MO 63106
SAINT LOUIS, MO 63106
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 Colin Diffie's NPI number?
The NPI number for Colin Diffie is 1942616404. It was assigned to this individual provider in the NPPES registry on July 5, 2014.
Where is Colin Diffie located?
Colin Diffie practices at 915 N Grand Blvd, Saint Louis, MO 63106. The listed phone number is (314) 652-4100.
What is Colin Diffie's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Rheumatology, with taxonomy code 207RR0500X.
Is Colin Diffie enrolled in Medicare?
Yes. Colin Diffie is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organization bills Medicare for Colin Diffie's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Colin Diffie reassigns Medicare benefits to Washington University (Saint Louis, MO). The 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 Colin Diffie's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Colin Diffie accept?
Health plans from Cox HealthPlans and UnitedHealthcare list Colin Diffie as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
Is Colin Diffie affiliated with any hospitals?
According to CMS data, Colin Diffie is affiliated with Memorial Hospital, Barnes Jewish Hospital, Missouri Baptist Medical Center, Barnes-Jewish West County Hospital and Parkland Health Center.
When was this NPI record last updated?
The NPPES record for Colin Diffie was last updated on September 11, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 13 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. Colin E Diffie, MD · NPI 1942616404
Rheumatology physician in Saint Louis, Missouri. Individual provider, active in the CMS NPPES registry since July 5, 2014.
## Identity
- **NPI:** 1942616404 (Entity type: Individual)
- **Enumerated:** July 5, 2014
- **Primary specialty:** Internal Medicine - Rheumatology · taxonomy 207RR0500X
- **State license:** 2019017299 (Missouri)
- **Sole proprietor:** No
## Practice location
- **Address:** 915 N GRAND BLVD, Saint Louis, MO 63106-1621
- **Phone:** (314) 652-4100 · **Fax:** (314) 289-6442
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** Washington University (NPI 1992746903, Saint Louis, MO), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2014
## Record status
- **NPPES last updated:** September 11, 2025
- **Other identifiers:** Medicaid 200061863 (MO)
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Source: [NPI Profile](https://npiprofile.com/npi/1942616404) · Data from the CMS NPPES public registry.