Another simple technique to calculate time difference in Excel is using the TEXT function: 1  Calculate hours between two times: =TEXT(B2-A2, h) 2  Return hours and minutes between 2 times: =TEXT(B2-A2, h:mm) 3  Return hours, minutes and seconds between 2 times: =TEXT(B2-A2, h:mm:ss)
Because cortisol levels change throughout the day, the timing of a cortisol test is important. A cortisol blood test is usually done twice a dayâonce in the morning when cortisol levels are at their highest, and again around 4 p.m., when levels are much lower. Cortisol may also be measured in a urine or saliva test. For a cortisol urine test, your health care provider may ask you to collect all urine during a 24-hour period. This is called a 24-hour urine sample test. It is used because cortisol levels vary throughout the day.
1 Cortisol levels are used, along with ACTH and ACTH stimulation tests, to help diagnose adrenal insufficiency. 2  ACTH. 3  ACTH is a pituitary hormone that signals the adrenal glands to produce cortisol. 4  This test is primarily ordered as a baseline test to evaluate if the pituitary is producing appropriate amounts of ACTH. If the adrenal gland is either not functioning normally or not being stimulated by ACTH, then cortisol levels will be consistently low. 2  Cortisol levels are used, along with ACTH and ACTH stimulation tests, to help diagnose adrenal insufficiency.