In congenital adrenal hyperplasia (CAH), lifelong hormone replacement therapy is required to treat adrenal insufficiency and to reduce elevated androgen levels. This is essential to ensure "normal" growth and puberty. Replacement therapy includes hydrocortisone and 9α-fludrocortisone acetate (as a mineralocorticoid substitute). Defining appropriate criteria for evaluating therapeutic goals is a key component of patient follow-up.

Currently, monitoring is generally limited to the quantification of serum 17-hydroxyprogesterone (17OHP), testosterone (T) and delta-4 androstenedione (D4), measured in the morning after an overnight fast and before the morning hydrocortisone dose. However, such single-point serum measurements do not take into account the circadian rhythm of these steroids.

The objective of the study is to evaluate correlations between steroid levels (21-deoxycortisol, 17-hydroxyprogesterone, testosterone, delta-4 androstenedione, and cortisol) measured by LC-MS/MS in multiple at-home self-collected saliva samples and those measured in serum during routine monitoring.