Amy Gerson, PHD
Amy Gerson, PHD is a Health Service Psychologist in Lexington, MA, registered under NPI 1316087901. This provider registers 6 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 21A MUZZEY ST, Lexington, MA 02421. 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 |
|---|---|---|
| 4753 | MA | Health Service Psychologist primary |
| 4753 | MA | Adult Development & Aging Psychologist |
| 4753 | MA | Counseling Psychologist |
| 4753 | MA | Clinical Child & Adolescent Psychologist |
| 4753 | MA | Family Psychologist |
| 4753 | MA | Psychologist |
This provider holds licence 4753 issued in MA. 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 Health Service covers
A psychologist, certified/licensed at the independent practice level in his/her state, who is duly trained and experienced in the delivery of direct, preventative, assessment, and therapeutic intervention services to individuals whose growth, adjustment, or functioning is actually impaired or is demonstrably at high risk of impairment (1974). NUCC Health Care Provider Taxonomy, code 103TH0100X
All registered taxonomy codes
This provider registers 6 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 103TH0100X | Health Service Psychologist Health Service | 4753 | MA | primary |
| 103TA0700X | Adult Development & Aging Psychologist Adult Development & Aging | 4753 | MA | |
| 103TC1900X | Counseling Psychologist Counseling | 4753 | MA | |
| 103TC2200X | Clinical Child & Adolescent Psychologist Clinical Child & Adolescent | 4753 | MA | |
| 103TF0000X | Family Psychologist Family | 4753 | MA | |
| 103T00000X | Psychologist | 4753 | MA |
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 | 1316087901 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Feb 6, 2007 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | PHD |
| Practice address |
21A MUZZEY ST Lexington, MA 02421 (781) 862-5623 Fax (781) 860-5268 |
| Mailing address |
12 CLEMATIS RD Lexington, MA 02421 |
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 | 3 | 1 | 6 | 0 | 8 | 7 | 9 | 0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 3 | 2 | 6 | 0 | 8 | 5 | 9 | 0 |
Sum = 59 · next multiple of 10 = 60 · check digit = 1 · actual last digit = 1
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.