Is fasting required for cortisol testing?
Disease description:
I've recently felt somewhat overweight and suspect it might be due to high cortisol levels. My doctor recommended testing cortisol. Do I need to fast before the cortisol test?
Doctor's answer (1)
Dr. Yang Ziqi
Cortisol testing generally does not require fasting.
Under normal circumstances, cortisol testing involves three blood draws: the first is usually around 8 a.m., the second around 4 p.m., and the third around midnight.
Typically, blood cortisol levels are highest around 8 a.m., lower in the afternoon at around 4 p.m. compared to the morning, and usually at their lowest at midnight.
