A.. MASTEN, M.D. appears in the CMS NPPES registry as a Clinical & Laboratory Dermatological Immunology Physician provider holding M.D. credentials at 509 LAKEVIEW AVE, MILFORD, DE, 19963, with a listed phone of (302) 422-4581. NPI 1083704472 was issued on 10/13/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what MASTEN most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D prescribing data is not currently published for this NPI, which typically means the provider either wrote fewer than 11 Part D claims in the most recent reporting year, does not participate in Medicare, or practices in a specialty that rarely prescribes outpatient drugs. Absence of prescribing data is not a quality signal — many Clinical & Laboratory Dermatological Immunology Physician providers operate outside Part D entirely.

Clinical & Laboratory Dermatological Immunology Physician is a narrow specialty nationwide, with 63 enrolled providers across 29 states and an average of 755 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.