To show the procalcitonin (PCT) test demand from an emergency department (ED) over several years, to decrease PCT measurement via a computerized algorithm based on C-reactive protein (CRP) value, and to evaluate the subsequent economic savings.A cross-sectional study was performed from January 1, 2018, to May 31, 2019, to evaluate an intervention to avoid PCT measurement in the ED of Hospital Universitario San Juan in Alicante in Spain, when CRP values are low.A PCT result of at least 1.5 ng/mL was agreed upon with ED providers in our study as the value for clinical decision-making, with values less than 1.5 ng/mL considered negative. We retrospectively reviewed all PCT and CRP values for ED patients and calculated the diagnostic indicators for PCT at 4 different CRP cutoffs using the PCT quantification as the gold standard. From July 1, 2019, to April 30, 2021, the agreed-upon strategy was implemented, and we counted the PCT tests avoided and calculated the savings.PCT was not measured when CRP values were less than the selected CRP cutoff of 0.8 mg/dL, at which false-negative results were 1% and the 99th percentile of PCT was 1.5 ng/mL. In the postintervention period, 1091 PCT values were not measured and $11,553.69 was saved.An intervention to decrease PCT measurement in the ED designed by the clinical laboratory staff in consensus with requesting clinicians and based on CRP values decreased PCT testing and generated significant economic savings.