Congenital Adrenal Hyperplasia (CAH) includes a group of disorders in which the cortisol production by adrenals is lowered. Cortisol is a steroid hormone necessary to maintenance of blood sugar level, partial maintenance of body fluids and electrolytes and protection of the body against stress. CAH cannot be cured, but it can be effectively treated by steroid substitution therapy if detected in early stage of life and disease course. Because of large individual variation in cortisol secretion, it is also important to monitor treatment very carefully. The means to determine an appropriate replacement dose includes measurement of serum/plasma17-hydroxyprogesterone. Labsystems Diagnostics' Neoscreen 17-OH-Progesterone FEIA test allows quantification of 17-hydroxyprogesterone in dried blood spot samples.