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.
Laboratory Tests. No single laboratory test is ideal to diagnose Cushing syndrome and more than one is often used. Since cortisol levels change over the course of a day, a single cortisol result from a blood sample drawn at most times of the day is of little value. Testing for Cushing syndrome is typically done in two stages. Initial tests are used to verify that there is excess cortisol present.