Mark Costanzo, MSW
Mark Costanzo, MSW is a provider specialising in School Social Worker in Denver, CO, registered under NPI 1275361024. 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 951 20TH STREET STE 1201,, Denver, CO 80201. 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 |
|---|---|---|
| LSW.0009925410 | CO | School Social Worker primary |
This provider holds licence LSW.0009925410 issued in CO. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
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.
What School covers
Definition to come... NUCC Health Care Provider Taxonomy, code 1041S0200X
All registered taxonomy codes
This provider registers 2 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 1041S0200X | School Social Worker School | LSW.0009925410 | CO | primary |
| 1041S0200X | School Social Worker School | — | — |
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 | 1275361024 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jul 23, 2024 |
| Last updated | Jul 31, 2024 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | MSW |
| Practice address |
951 20TH STREET STE 1201, Denver, CO 80201 |
| Mailing address |
PO BOX 752123 Houston, TX 77275 |
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 | 2 | 7 | 5 | 3 | 6 | 1 | 0 | 2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 2 | 5 | 5 | 6 | 6 | 2 | 0 | 4 |
Sum = 56 · next multiple of 10 = 60 · check digit = 4 · actual last digit = 4
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.