Iwata E, et al. - Using case-control study design, researchers sought to determine the laboratory markers for surgical site infection (SSI) which are not affected by operative factors. as well as the diagnostic cutoffs of these markers in posterior lumbar decompression surgery. They compared C-reactive protein level and total white blood cell count and differential count preoperatively and 1 and 4 days postoperatively, among patients who developed deep SSI (SSI group; n=8) and those that didn’t (n=174). They found that lymphocyte percentage at 4 days postoperatively (cutoff, < 19.4%; sensitivity, 80.0%; specificity, 62.5%; area under the curve, 0.78) and lymphocyte count at 4 days postoperatively (cutoff, < 1010/μL; sensitivity, 93.7%; specificity, 62.5%; area under the curve, 0.78) were reliable markers for SSI following posterior lumbar decompression surgery. Since lymphocyte count at 4 days postoperatively demonstrated a high sensitivity and could be measured early, it can be considered as a superior marker for screening.