Lawrence Mass, M.D.
Lawrence Mass, M.D. is an Addiction Medicine (Internal Medicine) Physician in New York, NY, registered under NPI 1609090349.
Getting there
The practice address on file is 435 2ND AVE, New York, NY 10010. 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 |
|---|---|---|
| 127475 | NY | Addiction Medicine (Internal Medicine)… primary |
This provider holds licence 127475 issued in NY. 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 Addiction Medicine covers
An internist doctor of osteopathy that specializes in the treatment of addiction disorders. A doctor of osteopathy that is board eligible/certified by the American Osteopathic Board of Internal Medicine can obtain a Certificate of Added Qualifications in the field of Addiction Medicine. NUCC Health Care Provider Taxonomy, code 207RA0401X
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 | 1609090349 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Apr 12, 2007 |
| Last updated | Dec 3, 2012 |
| Status | Active |
| Sole proprietor | No |
| Credential | M.D. |
| Practice address |
435 2ND AVE New York, NY 10010 (212) 726-6823 |
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 | 6 | 0 | 9 | 0 | 9 | 0 | 3 | 4 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 0 | 9 | 0 | 9 | 0 | 3 | 8 |
Sum = 61 · next multiple of 10 = 70 · check digit = 9 · actual last digit = 9
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.