A five year old boy presents with Precocious Pubey and a Blood Pressure of 130/80 mm Hg. Estimation of which of the following will help in diagnosis:

A male child presenting with early onset pubey and hypeension is suggestive of congenital adrenal hyperplasia due to the deficiency of 11-b hydroxylase deficiency. Ref: Essential Pediatrics By O P Ghai, 6th Edition, Page 490; Nelson's Textbook of Pediatrics, 18th Edition, Page 2362