The levels of CRP, ESR, sD-Dimer, and sFDP in Group A were significantly higher than the levels in Group B. The AUC values, optimal threshold values, sensitivity, and specificity for CRP, ESR, sD-Dimer, and sFDP in PJI diagnosis were as follows: CRP [0.920 (95% confidence interval (CI), 0.846–0.965), >6.77, 76.69%, 95.00%], ESR [0.905 (95% CI, 0.828–0.955), >41, 73.21%, 92.50%], sD-Dimer [0.788 (95% CI, 0.692–0.864), >738.65, 66.07%, 80.00%], and sFDP [0.869 (95% CI, 0.785–0.929), >1558.35, 91.07%, 70.00%]. The gene discussed is CRP; the disease is juvenile polyposis syndrome.