Mark John Sey, M.D.
Pediatrics Physician · Philadelphia, PA
Mark John Sey, M.D. is a pediatrics physician with a practice address in Philadelphia, Pennsylvania, and NPI 1366494718, issued on May 16, 2006. Check the license (Pennsylvania MD011601E, as entered in NPPES) on the Pennsylvania Department of State (PALS); the Medicare figures below come from public CMS files.
- Name
- Mark John Sey
- Credential
- M.D.
- Primary taxonomy
- Pediatrics Physician 208000000X
- License number
- MD011601E PA
Self-reported in NPPES; status is on the state search - Practice location
- 6608 Castor Ave, Philadelphia, PA 19149
- Phone
- (215) 342-7711
- Enumerated
- May 16, 2006
- Record last updated
- Apr 4, 2013 (not updated in 13 years: call before relying on the address or phone)
- Fax
- (215) 722-8712
- Medicaid ID
- 0681843 PA
- Entity
- Type 1 · individual
8 nearest pediatrics physician records → All 3,382 in Pennsylvania → Look up another NPI →
Also registered at 6608 Castor Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Paige Blumenthal, CRNPPediatric Nurse Practitioner1972013118
- Elizabeth Bowman, CRNPFamily Nurse Practitioner1194048025
- Nancy Buckley, MDPediatrics Physician1215922075
- Denise CarrPediatric Nurse Practitioner1639504434
- Fred Carroll, M.D.Pediatrics Physician1336427111
- Samantha Feinberg, PA-CPhysician Assistant1457836082
Verify Mark John Sey in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersPennsylvania Department of State (PALS)
Search for license MD011601ECheck the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
94% fewer Medicare Part D claims than the average pediatrics physician in 2024
24 Medicare Part D claims, against an average of 375 among the 5,609 providers of this specialty who prescribed in Part D.
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Mark John Sey among 3,382 pediatrics physician records in Pennsylvania
Mark John Sey, M.D. is one of 3,382 pediatrics physician records with a practice address in Pennsylvania. 25% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 12% of them.
- NPI issued2006 · 12% of these records are older, 58% newer
- In a Medicare fileYes · 25% of these records are
- In the CMS Doctors and Clinicians fileNo · 7% of these records are
- Record last updated2013 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 208000000X and a Pennsylvania practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
1,153 pediatrics physician records list a practice address in Philadelphia
They are 1,153 of the 42,849 NPPES records with a practice address in Philadelphia, and 3,382 pediatrics physician records in Pennsylvania.
All 3,382 in Pennsylvania → Every provider in Philadelphia → Pediatrics Physician nationwide →
The 8 pediatrics physician records with the nearest ZIP codes
- Nancy Buckley, MDPhiladelphia, PA 191491215922075
- Fred Carroll, M.D.Philadelphia, PA 191491336427111
- Kelsea Green, CRNPPhiladelphia, PA 191491477344943
- Vladimir Perelshteyn, M.D.Philadelphia, PA 191491144233917
- Emma Rajaratnam, M.D.Philadelphia, PA 191491265445761
- Karen Trabulsi, M.D.Philadelphia, PA 191491831202332
- Elisa Vengalil, MDPhiladelphia, PA 191491518545227
- Stephen Levin, MDPhiladelphia, PA 191501700857042
Common questions
What is Mark John Sey, M.D.'s NPI number?
Mark John Sey, M.D.'s National Provider Identifier (NPI) is 1366494718, issued on May 16, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mark John Sey, M.D. located?
The NPPES record lists a practice address at 6608 Castor Ave, Philadelphia, PA, 19149. Phone: (215) 342-7711. Providers update this record themselves, so call before visiting.
How can I verify Mark John Sey, M.D.'s license?
NPPES lists Pennsylvania license number MD011601E, as entered by the provider. Search the Pennsylvania Department of State (PALS) at https://www.pals.pa.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Mark John Sey, M.D. prescribe under Medicare Part D?
In 2024, Mark John Sey, M.D. had 24 Medicare Part D claims; the average among pediatrics physician prescribers was 375. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.