WILLIAM GRASS, ARNP appears in the CMS NPPES registry as a Critical Care Medicine Nurse Practitioner provider holding ARNP credentials at 10 BARNES WEST DR, CREVE COEUR, MO, 63141, with a listed phone of (314) 996-8270. NPI 1407854383 was issued on 07/13/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what GRASS 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 records for calendar year 2023 show 225 prescription claims written by this provider, covering 105 Medicare beneficiaries and totaling roughly $10K in drug spend, split 10% brand-name and 90% generic by claim count. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Critical Care Medicine Nurse Practitioner is a narrow specialty nationwide, with 1,410 enrolled providers across 50 states and an average of 426 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.