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.
If you do not have this daily change (diurnal rhythm) in cortisol levels, you may have overactive adrenal glands. This condition is called Cushing's syndrome. The timing of the cortisol test is very important because of the way cortisol levels vary throughout a day.f you do not have this daily change (diurnal rhythm) in cortisol levels, you may have overactive adrenal glands. This condition is called Cushing's syndrome. The timing of the cortisol test is very important because of the way cortisol levels vary throughout a day.