MARIANA RODRIGUEZ FIERRO, RDN, CDCES appears in the CMS NPPES registry as a Registered Dietitian provider holding RDN, CDCES credentials at 420 W WATKINS ST, PHOENIX, AZ, 85003, with a listed phone of (623) 850-1143. NPI 1861361776 was issued on 10/30/2025. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what RODRIGUEZ FIERRO 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 Registered Dietitian providers operate outside Part D entirely.

Registered Dietitian is a high-volume specialty nationwide, with 64,100 enrolled providers across 55 states and an average of 696 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.