Objective A service evaluation project was conducted to design a pharmaceutical assessment screening tool (PAST) to assign all inpatients a patient acuity level (PAL) to then help teams of clinical pharmacists prioritise the frequency of, and the seniority of, pharmacists performing patient reviews; assess clinical pharmacists' adherence to the tool; and identify when pharmacists do not adhere to the tool. Methods The PAST was developed by consensus methodology to prioritise departmental workflow for clinical pharmacists. The most pharmaceutically complex patients at the greatest risk of adverse drug events were expected to receive a PAL score of 3, while the least complex receive a PAL of 1. A quasi-experimental service evaluation study was conducted 6 months after implementation of the tool to quantify agreement between pharmacist-documented and expected per-guidance PALs. Patients were selected via random clusters from wards. For each patient, a PAL was calculated by the researcher and compared with the pharmacist-documented PAL.