Test Background 17OHP is a precursor of cortisol, the major glucocorticoid synthesised in the adrenal cortex. Congenital adrenal hyperplasia (CAH) results in excessive ACTH secretion due to impairment in the synthesis of cortisol. A variety of enzyme defects in the pathway to cortisol synthesis have been identified, of which the most common is a 21-hydroxylase deficiency; 17OHP is the substrate for this enzyme. The serum 17OHP levels are significantly elevated in this condition.
Clinical Indications Ambiguous neonatal genitalia (female infants) ’Salt-wasting’ clinical symptoms (dehydration, vomiting, listlessness) Precociousness or failure of puberty Virilisation