Older studies proposed the 1 μg ACTH test in order to test for various degrees of adrenal insufficiency prior to steroid withdrawal [104]: 60% of KTR under steroid treatment for a mean period of 78 weeks had a borderline (peak cortisol to 1 μg ACTH test < 18 μg/dL, but 8 am serum cortisol > 5 μg/dL) or abnormal adrenal reserve (peak cortisol to 1 μg ACTH test < 18 μg/dL and 8 am serum cortisol < 5 μg/dL). This evidence concerns the gene POMC and Adrenal insufficiency.