IL1B and delirium: Using all values including those extrapolated from the standard curve, CSF IL-1β was higher in the group with delirium at any stage (median 1.02 pg/ml; IQR 0.66–1.74) compared to the no delirium group (median 0.66 pg/ml; IQR 0–1.02) (Mann Whitney U p = 0.02).