John Graef, M.D.
John Graef, M.D. is a Pediatric Medical Toxicology Physician in Boston, MA, registered under NPI 1982680575. This provider registers 3 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 333 LONGWOOD AVE, Boston, MA 02115. 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 |
|---|---|---|
| 33948 | MA | Pediatric Medical Toxicology Physician primary |
| 33948 | MA | Pediatrics Physician |
| 33948 | MA | Hospitalist Physician |
This provider holds licence 33948 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 Medical Toxicology covers
Medical toxicologists are physicians that specialize in the prevention, evaluation, treatment and monitoring of injury and illness from exposures to drugs and chemicals, as well as biological and radiological agents. Medical toxicologists care for people in clinical, academic, governmental and public health settings, and provide poison control center leadership. Important areas of medical toxicology include acute drug poisoning, adverse drug events, drug abuse, addiction and withdrawal, chemicals and hazardous materials, terrorism preparedness, venomous bites and stings, and environmental and workplace exposures. NUCC Health Care Provider Taxonomy, code 2080T0002X
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 | |
|---|---|---|---|---|
| 2080T0002X | Pediatric Medical Toxicology Physician Medical Toxicology | 33948 | MA | primary |
| 208000000X | Pediatrics Physician | 33948 | MA | |
| 208M00000X | Hospitalist Physician | 33948 | 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 | 1982680575 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Dec 16, 2005 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | M.D. |
| Practice address |
333 LONGWOOD AVE Boston, MA 02115 (617) 355-8263 Fax (617) 277-8934 |
| Mailing address |
147 MILK STREET PROVIDER ENROLLMENT - 9TH FLOOR Boston, MA 02109 |
| Other identifiers |
V02406
· Other (MA) PP624 · Other (MA) 0003908 · Other (MA) 2020785 · Medicaid (MA) 4147717-003 · Other (MA) 715698 · Other (MA) |
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 | 9 | 8 | 2 | 6 | 8 | 0 | 5 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 9 | 7 | 2 | 3 | 8 | 0 | 5 | 5 |
Sum = 65 · next multiple of 10 = 70 · check digit = 5 · actual last digit = 5
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.