Aim: The aim of this study was to examine whether a set of routine preoperative blood tests including WBCC, CRP, Creatinine (eGFR), albumin and hemoglobin predict the risk of SSI either alone or in combination. Methods: The observational cohort study was designed to evaluate the optimal timing of surgical antimicrobial prophylaxis. The preoperative blood test parameters hemoglobin, creatinine, albumin, CRP and white blood cell count were collected in those patients considered to have an indication for preoperative blood testing as per clinical standards. A total of 200 patients were included in the analysis for the RCT and hence assessed for the availability of preoperative levels of the blood parameters of interest