We found that bacteremia incidence was 9.1% and 25.4% for <0.5 and 0.5 to <2 ng/dL, respectively, but higher likelihoods could be targeted through clinical prediction modeling to >24% and >40% for these cutoffs if restricted to medium- and high-risk-prediction-model patients, reflecting the synergistic value of PCT and clinical prediction models for determining patients who are likely bacteremic. This evidence concerns the gene CALCA and bacterial infectious disease with sepsis.