Aim: SeptiCyte LAB measures the expression of four host-response RNAs in blood to distinguish sepsis from sterile inflammation. Sequential monitoring of this assay may have diagnostic utility in patients at high risk for postoperative infectious complications.
Methods: In this pilot study we studied esophagectomy patients who had developed a complication within 30 days following surgery as well as a random sample of 100 uncomplicated postoperative patients. PAXgene blood samples were collected postoperatively and whenever a complication occurred. SeptiCyte scores (ranging 0-10 with increasing likelihood of infection) were compared to post-hoc physician adjudication of infection likelihood using strict definitions.
Results: Among 370 esophagectomy patients, 120 (32%) subjects developed a complication requiring ICU (re)admission, 63 (53%) of whom could be analyzed. Immediate postoperative SeptiCyte LAB scores were highly variable, yet similar for patients having a complicated and uncomplicated postoperative course (median score of 2.4 (IQR 1.6-3.3) versus 2.2 (IQR 1.3-3), respectively). Scores increased as complications developed, but this rise was higher for 34 subjects having confirmed infection (median difference 4.7 (IQR 4.1-5.8)) then for 12 subjects with a non-infectious complication (2.1 (IQR 0.4-3.6); p<0.0001). When 17 cases with undetermined infectious status were excluded, addition of SeptiCyte LAB to CRP resulted in improved diagnostic discrimination (AUC 0.88 (95%CI 0.77-0.99)) compared to CRP alone (AUC 0.76 (95%CI 0.61-0.91); p=0.04).
Conclusions: Sequential measurement of SeptiCyte LAB may have clinical utility in surgical patients at high risk of postoperative infection, but its diagnostic performance in this setting needs to be further evaluated.