Among the two biomarker combinations, we found that a combination of plasma fibrinogen and CRP was associated with a high AUC (0.897, 95% CI 0.816–0.978), an acceptable sensitivity (75%), and the highest specificity (93.5%); the highest PPV (92.3%) and acceptable NPV (78.4%) associated with this combination indicate its effectiveness in diagnosing PJI before re-revision arthroplasty. The gene discussed is CRP; the disease is juvenile polyposis syndrome.