MARK JOHNSON, PA-C MT ASCP appears in the CMS NPPES registry as a Physician Assistant provider holding PA-C MT ASCP credentials at 300 1ST CAPITOL DR, SAINT CHARLES, MO, 63301, with a listed phone of (636) 947-5000. NPI 1568453132 was issued on 11/02/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what JOHNSON 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 298 prescription claims written by this provider, covering 196 Medicare beneficiaries and totaling roughly $5K in drug spend, with an opioid prescribing rate of 17.4%. 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.

Physician Assistant is a high-volume specialty nationwide, with 149,975 enrolled providers across 56 states and an average of 790 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.