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My doctor ordered a cortrosyn stimulation test. Does this have to be done at 8am like my previos cortisol test or is time not a factor?

5 doctors weighed in
Dr. Susan Wingo
Internal Medicine - Endocrinology
2 doctors agree

In brief: It depends.

Usually, a Cortrosyn Stimulation Test give 4 results: ACTH(Baseline) & Cortisol(Baseline, 30', & 60').
The baseline ACTH & Cortisol are affected by time of day, and should be done as close as possible to your usual wake-up time (Traditionally ordered as 8AM). However, the most important values are the 30' & 60' Cortisols - these determine whether or not your adrenals can make enough Cortisol.

In brief: It depends.

Usually, a Cortrosyn Stimulation Test give 4 results: ACTH(Baseline) & Cortisol(Baseline, 30', & 60').
The baseline ACTH & Cortisol are affected by time of day, and should be done as close as possible to your usual wake-up time (Traditionally ordered as 8AM). However, the most important values are the 30' & 60' Cortisols - these determine whether or not your adrenals can make enough Cortisol.
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Dr. Susan Wingo
If the 30- & 60-minute results are normal, the baseline values aren't as important. However, if these results are low, the baseline values are very important to determine whether the failure of the adrenals to make enough Cortisol is due to a problem in the adrenal glands themselves, or a problem with the pituitary gland (the "master gland" just below the brain) which controls the adrenals.
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