Jack Cossman, MD
Jack Cossman, MD is a Dermatology Physician in New Haven, CT, registered under NPI 1912318304. 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 20 YORK ST YALE NEW HAVEN HOSPITAL, New Haven, CT 06510. 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 |
|---|---|---|
| MD28358 | ME | Dermatology Physician primary |
This provider holds licence MD28358 issued in ME. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
- Status
- Approved
- Provider type
- Practitioner - Dermatology
- PAC ID
- 3779831177
Enrolled in Medicare 4 times, across 4 states:
| State | Enrollment ID | Provider type |
|---|---|---|
| New York | I20180801001581 | Practitioner - Dermatology |
| New Jersey | I20221212001741 | Practitioner - Dermatology |
| California | I20230807000579 | Practitioner - Dermatology |
| Maine | I20250929002970 | Practitioner - Dermatology |
Medicare enrolment is recorded as approved under the provider type Practitioner - Dermatology. There are 4 separate enrolment records across 4 states (NY, NJ, CA, ME). Multiple enrolments usually mean the provider bills Medicare from more than one practice location, or has kept an earlier enrolment after moving. Each record carries its own enrolment ID, listed above. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
What Dermatology covers
A dermatologist is trained to diagnose and treat pediatric and adult patients with benign and malignant disorders of the skin, mouth, external genitalia, hair and nails, as well as a number of sexually transmitted diseases. The dermatologist has had additional training and experience in the diagnosis and treatment of skin cancers, melanomas, moles and other tumors of the skin, the management of contact dermatitis and other allergic and nonallergic skin disorders, and in the recognition of the skin manifestations of systemic (including internal malignancy) and infectious diseases. Dermatologists have special training in dermatopathology and in the surgical techniques used in dermatology. They also have expertise in the management of cosmetic disorders of the skin such as hair loss and scars and the skin changes associated with aging. NUCC Health Care Provider Taxonomy, code 207N00000X
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 | |
|---|---|---|---|---|
| 207N00000X | Dermatology Physician | MD28358 | ME | primary |
| 390200000X | Student in an Organized Health Care Education/Training Program | — | — |
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 | 1912318304 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | May 19, 2014 |
| Last updated | Jul 1, 2024 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | MD |
| Practice address |
20 YORK ST YALE NEW HAVEN HOSPITAL New Haven, CT 06510 (203) 688-4242 |
| Mailing address |
3602B LONG BEACH BLVD Beach Haven, NJ 08008 |
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 | 1 | 2 | 3 | 1 | 8 | 3 | 0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 9 | 2 | 2 | 6 | 1 | 7 | 3 | 0 |
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.