17 hydroxyprogesterone (17 OHP) is an inactive steroid hormone produced mainly in the adrenal cortex. It is a precursor hormone that is converted into the active hormone cortisol. Several enzymes are needed to complete this conversion to cortisol. If one or more of these enzymes is deficient or dysfunctional, an inadequate amount of cortisol is produced causing 17 OHP and other androgens to be produced in excess. This excess 17 OHP is seen in an inherited condition called congenital adrenal hyperplasia (CAH). CAH is a group of inherited disorders caused by gene mutations associated with cortisol-related enzyme deficiencies. The severe form of CAH can cause life-threatening salt wasting crisis in newborn infants and often causes ambiguous genitalia. Due to the disrupted hypothalamus-pituitary-adrenal axis, the 17 OHP laboratory test is often done in conjunction with other endocrine laboratory tests: ACTH, renin, and androstenedione.