Figure 4.

Acoustic-enhanced flow cytometry can be used to confirm clinical suspicion of peritonitis. a) Using the method as outlined across a teaching set of data (n= 72 culture positive peritonitis specimens, n=16 culture negative peritonitis specimens, and n=16 non-infectious specimens taken from hospital in-patients with no clinical suspicion of peritonitis) there were significant differences in cell-like events/mL assayed for each group (Kruskal–Wallis P<0.001). b) Across a teaching set (n=15 culture positive peritonitis, n= 5 culture negative peritonitis, and n=10 specimens from patient submitted with suspicion of peritonitis but later found to be uninfected), using a cut-off value of 9.5×10⁴ cell-like events/mL, 29 of 30 specimens were correctly classified as “peritonitis” or “not peritonitis”. c) Comparing non-infectious specimens from the teaching set with the “not peritonitis” specimens from the testing set, there were no statistically significant differences in numbers of cell-like events/mL (unpaired t-test, P= 0.94, ns). d) The testing set performance showed sensitivity and specificity in line with the teaching set optimisation (within appropriate confidence limits). Box plots, where presented, show mid-line as median, with whiskers as min-max.