U40 Supplement is a filter-sterilized urea solution for detecting urease activity in micro-organisms. Each vial, sufficient for 100 ml of medium, supplies sterile urea at final pH 8.0 and is simply warmed and added aseptically to molten Urea Broth or Urea Agar Base (Christensen). Organisms that hydrolyse urea release ammonia, shifting the indicator to a distinct pink and confirming a positive result, a key step in identifying Proteus, Klebsiella and related genera. Store at 2 to 8 C. Packaged as 5 vials.