Serum (Gold Top)
North Devon District Hospital (24/7)
Interpretation of 9am sample:
Cortisol <170 suggestive of adrenal insufficiency
Cortisol >320 adrenal failure unlikely if no symptoms
Cortisol >420 usually excludes adrenal insufficiency
Indicate time of sampling
If taking supplements which contain Biotin (Vitamin B7), do not take in the 8 hours prior to blood test - the concentration present may affect the accuracy of the test.