I took my 15 year old daughter for a blood test today and the nurse didn't know what an NBT was that was ordered on the form so she rang the childrens hospital. Then she told us this test would have to be done on wednesday morning as the courier would have to take it straight to the hospital within 4 hours. When i got home i googled it and found that they were looking for chronic granulomatous disease. Is this disease common with crohns and why would they want the blood there straight away ?