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.
Free cortisol is secreted into the urine and is present in the saliva. This test measures the amount of cortisol in the blood, urine, or saliva. The level of cortisol in the blood (as well as the urine and saliva) normally rises and falls in a diurnal variation pattern.his test measures the amount of cortisol in the blood, urine, or saliva. The level of cortisol in the blood (as well as the urine and saliva) normally rises and falls in a diurnal variation pattern.