Mary8 Halas, PHD
Mary8 Halas, PHD is a Clinical Psychologist in Alexandria, VA, registered under NPI 1033236096. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 50 S PICKETT ST SUITE 224, Alexandria, VA 22304. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| 1198 | VA | Professional Counselor |
| 1196 | AZ | Clinical Psychologist |
| 2126 | MD | Clinical Psychologist primary |
Licences are recorded in 3 states: VA, AZ, MD. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
Licensed in 3 states
This provider holds licences in 3 states: Arizona, Maryland and Virginia. The practice address on file is in Alexandria, VA, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.
Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.
What Clinical covers
A psychologist who provides continuing and comprehensive mental and behavioral health care for individuals and families; consultation to agencies and communities; training, education and supervision; and research-based practice. It is a specialty in breadth -- one that is broadly inclusive of severe psychopathology -- and marked by comprehensiveness and integration of knowledge and skill from a broad array of disciplines within and outside of psychology proper. The scope of clinical psychology encompasses all ages, multiple diversities and varied systems. NUCC Health Care Provider Taxonomy, code 103TC0700X
All registered taxonomy codes
This provider registers 3 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 101YP2500X | Professional Counselor Professional | 1198 | VA | |
| 103TC0700X | Clinical Psychologist Clinical | 1196 | AZ | |
| 103TC0700X | Clinical Psychologist Clinical | 2126 | MD | primary |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1033236096 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Mar 23, 2007 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Gender | Female |
| Credential | PHD |
| Practice address |
50 S PICKETT ST SUITE 224 Alexandria, VA 22304 (703) 823-0801 Fax (703) 823-0802 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 0 | 3 | 3 | 2 | 3 | 6 | 0 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 6 | 3 | 4 | 3 | 3 | 0 | 9 |
Sum = 54 · next multiple of 10 = 60 · check digit = 6 · actual last digit = 6
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.