Division of Chemistry and Toxicology
	Congenital Adrenal Hyperplasia Unit

		Congenital adrenal hyperplasia (CAH) is a hereditary autosomal recessive disorder. It is caused by enzyme defects in steroid synthesis. The most frequent types are21-hydroxylase and 11-hydroxylase deficiencies (95%). These enzyme deficiencies cause the build up of precursors, notably 17-OH Progesterone (17-OHP). Biosynthesis is shunted to other pathways causing decreased production of cortisol which can lead to adrenal failure and increased production of the adrenal androgens resulting in virilization. Early detection and treatment is essential for the life-threatening, salt-wasting form (50-80%) and correct gender assignment for virilized females.

 

	Principles of the Test
		The procedure used in the laboratory is quantitative determination of 17-OHP and is used clinically as a neonatal screening method for CAH.   This procedure is performed on the AutoDELFIA manufactured by Wallac, Inc. It is a solid phase, time-resolved fluroroimmunoassay based on competitive binding between europium-labeled 17-OHP and sample 17-OHP for a limited number of binding sites. Enhancement Solution dissociates europium ions from the labeled antibody into solution, where they form highly fluorescent chelates.   The fluorescence for each sample is measured and is inversely proportional to the quantity of 17-OHP. Caron Burns Phone: 517-335-9937 burnscar@state.mi.us