MARY DEIRDRE JOHNSTON MD
NPI 1881670958
Psychiatry & Neurology - Geriatric Psychiatry in Baltimore, MD
About Mary Deirdre Johnston Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARY DEIRDRE JOHNSTON MD (NPI 1881670958) is an individual geriatric psychiatry provider in Baltimore, Maryland, licensed in North Carolina (9500105) and active in the NPI registry since December 2005. She is enrolled in Medicare PECOS.
NPPES Registry Identity
Specialties & Licenses
Other Identifiers 2
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare (PECOS)
Mary Deirdre Johnston Md is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignment
Medicare enrollment records show Mary Johnston reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Baltimore, MD 21287
- Reassigned Medicare billing, Maryland enrollment
- 4,483 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 21287 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 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
BALTIMORE, MD 21287
BALTIMORE, MD 21287
BALTIMORE, MD 21287
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 Mary Johnston's NPI number?
The NPI number for Mary Johnston is 1881670958. It was assigned to this individual provider in the NPPES registry on December 20, 2005.
Where is Mary Johnston located?
Mary Johnston practices at 600 N Wolfe Street Johns Hopkins University School Of Medicine, Baltimore, MD 21287. The listed phone number is (410) 955-5147.
What is Mary Johnston's specialty?
The primary specialty registered for this NPI is Psychiatry & Neurology, specializing in Geriatric Psychiatry, with taxonomy code 2084P0805X.
Is Mary Johnston enrolled in Medicare?
Yes. Mary Johnston is registered in the Medicare PECOS enrollment system.
Which organization bills Medicare for Mary Johnston's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mary Johnston reassigns Medicare benefits to Johns Hopkins University (Baltimore, MD). 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 Mary Johnston'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 Mary Johnston was last updated on September 18, 2012. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 14 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.
# Mary Deirdre Johnston, MD · NPI 1881670958
Geriatric Psychiatry physician in Baltimore, Maryland. Individual provider, active in the CMS NPPES registry since December 20, 2005.
## Identity
- **NPI:** 1881670958 (Entity type: Individual)
- **Enumerated:** December 20, 2005
- **Primary specialty:** Psychiatry & Neurology - Geriatric Psychiatry · taxonomy 2084P0805X
- **State license:** 9500105 (North Carolina)
- **Sole proprietor:** No
## Practice location
- **Address:** 600 N WOLFE STREET, JOHNS HOPKINS UNIVERSITY SCHOOL OF MEDICINE, Baltimore, MD 21287-7279
- **Phone:** (410) 955-5147
## 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:** Johns Hopkins University (NPI 1023018413, Baltimore, MD), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** September 18, 2012
- **Other identifiers:** Medicare ID-Type Unspecified 2215758A (NC); Medicare UPIN G22057
---
Source: [NPI Profile](https://npiprofile.com/npi/1881670958) · Data from the CMS NPPES public registry.