TNF and inflammatory bowel disease: The mean sweat TNF-α level for subjects with IBD, in a  ± 30 min window around serum measurements, was 1.541 pg/ml (std = 0.46), while in healthy controls it was 0.3508 pg/ml (std = 0.37), over a 1 h window approximately 30–60 min after applying the device in the morning.