DR. JOHN WHITNEY MERCER JR. MD
NPI 1205988540
Obstetrics & Gynecology in Nampa, ID
About Dr. John Whitney Mercer Jr. Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. JOHN WHITNEY MERCER JR. MD (NPI 1205988540) is an individual obstetrics & gynecology provider in Nampa, Idaho, licensed in Idaho (3971468) and active in the NPI registry since January 2007. He is enrolled in Medicare PECOS, is affiliated with Minden Medical Center, and maintains 2 additional practice locations.
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Locations 2
Other Identifiers 3
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. John Whitney Mercer Jr. 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 Reassignments
8Medicare enrollment records show John Mercer reassigns Medicare billing to 8 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Caldwell, ID 83605
- Reassigned Medicare billing, Idaho enrollment
- 781 clinicians in this Medicare group
Craig, CO 81625
- Reassigned Medicare billing, Colorado enrollment
- 438 clinicians in this Medicare group
Casper, WY 82601
- Reassigned Medicare billing, Wyoming enrollment
- 17 clinicians in this Medicare group
Casper, WY 82601
- Reassigned Medicare billing, Wyoming enrollment
- 16 clinicians in this Medicare group
Colorado Springs, CO 80920
- Reassigned Medicare billing, Colorado enrollment
- Medicare enrollment name: Obhg Colorado PC
- 66 clinicians in this Medicare group
Springhill, LA 71075
- Reassigned Medicare billing, Louisiana enrollment
- 83 clinicians in this Medicare group
Alexandria, LA 71301
- Reassigned Medicare billing, Louisiana enrollment
- 34 clinicians in this Medicare group
Greenville, SC 29607
- Reassigned Medicare billing, Louisiana enrollment
- 108 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.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Minden Medical Center
Acute Care Hospitals · Minden, LAPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 83687 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 4
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
NAMPA, ID 83687
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 John Mercer's NPI number?
The NPI number for John Mercer is 1205988540. It was assigned to this individual provider in the NPPES registry on January 17, 2007.
Where is John Mercer located?
John Mercer practices at 4424 E Flamingo Ave Ste 200, Nampa, ID 83687. The listed phone number is (208) 302-1400.
What is John Mercer's specialty?
The primary specialty registered for this NPI is Obstetrics & Gynecology with taxonomy code 207V00000X.
Is John Mercer enrolled in Medicare?
Yes. John Mercer 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 organizations bill Medicare for John Mercer's services?
According to the CMS Revalidation Reassignment List (October 2026 release), John Mercer reassigns Medicare benefits to 8 organizations: Saint Alphonsus Regional Medical Center Inc (Caldwell, ID), Intermountain Medical Group Grand Junction, LLC (Craig, CO), Casper Obstetrical And Gynecological Associates PC (Casper, WY), Obhg Wyoming PC (Casper, WY), Obhg Colorado, P.C. (Colorado Springs, CO) and 3 more organizations, 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 John Mercer's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does John Mercer accept?
Health plans from Ambetter Health, Ambetter from Arkansas Health & Wellness, Ambetter from Louisiana Healthcare Connections, Ambetter from Superior HealthPlan and Blue Cross Blue Shield of Wyoming and 2 other insurers list John Mercer 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 John Mercer affiliated with any hospitals?
According to CMS data, John Mercer is affiliated with Minden Medical Center.
When was this NPI record last updated?
The NPPES record for John Mercer was last updated on September 2, 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. John Whitney Mercer Jr., MD · NPI 1205988540
Obstetrics & Gynecology physician in Nampa, Idaho. Individual provider, active in the CMS NPPES registry since January 17, 2007.
## Identity
- **NPI:** 1205988540 (Entity type: Individual)
- **Enumerated:** January 17, 2007
- **Primary specialty:** Obstetrics & Gynecology · taxonomy 207V00000X
- **State license:** 3971468 (Idaho)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 4424 E FLAMINGO AVE STE 200, Nampa, ID 83687-9300
- **Phone:** (208) 302-1400 · **Fax:** (208) 302-1455
## 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:** 8 organizations under Medicare reassignment (form CMS-855R): Saint Alphonsus Regional Medical Center Inc (NPI 1861676298, Caldwell, ID); Intermountain Medical Group Grand Junction, LLC (NPI 1245843481, Craig, CO); Casper Obstetrical And Gynecological Associates PC (NPI 1134272917, Casper, WY); Obhg Wyoming PC (NPI 1346055068, Casper, WY); Obhg Colorado, P.C. (NPI 1104116896, Colorado Springs, CO); and 3 more · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 1997
## Record status
- **NPPES last updated:** September 2, 2025
- **Other identifiers:** Other L023779 (LA); Medicaid 9000166884 (CO); Medicaid 1487163 (LA)
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Source: [NPI Profile](https://npiprofile.com/npi/1205988540) · Data from the CMS NPPES public registry.