Preoperative:
- Total counts, ESR (>30) and CPR (>10). If ESR and CRP are normal PJI is unlikely.
- Synovial fluid cell counts with percentage of polymorphonuclear (PMN) leucocyte and synovial culture have a high sensitivity and specificity for the diagnosis of septic arthritis and PJI. Cut off values for cells and % of PMN cells for diagnosis of PJI is based on the joint & time after surgery.